Top 50 API Marketplaces to List Your API or MCP 2026

The practical, data-rich guide to every marketplace where you can list your API or MCP server for maximum reach with minimum effort.

There are over 50 places where you can list your API or MCP server today, and most builders have listed on fewer than 5. The distribution gap between building a great API and getting it discovered is the single biggest bottleneck for independent API and MCP builders in 2026. You can have a perfectly designed, well-documented tool, but if it only exists on your GitHub repo, the only people who will find it are the ones already looking for you specifically.

This guide catalogs every significant marketplace, directory, and distribution channel where API and MCP server builders can list their products. For each one, we provide the exact URL to submit, what is required, how long it takes, the estimated reach, and whether listing is programmatic (your AI coder can do it), form-based (5 minutes of copy-paste), or complex (hours of prep and review processes). We then score every marketplace on Impact (reach times conversion quality) and Effort (time and cost to list), producing a single ranking that answers the question every builder wants answered: where should I list first?

Written by Yuma Heymans (@yumahey), whose team at O-mega recently listed the Suprsonic unified API and MCP server across 18 marketplaces in a single day, learning firsthand which platforms are worth the effort and which are not.

Contents

1. The Master Table: All 50 Marketplaces Ranked by Impact/Effort
2. Listing Categories: Programmatic, Form, and Complex
3. MCP Server Directories (The First 10 You Should List On)
4. API Marketplaces with Monetization
5. Integration Platforms (Zapier, Make, n8n, Pipedream)
6. Cloud Marketplaces (AWS, Azure, Google Cloud)
7. AI Tool Directories
8. Free API Directories (SEO Value)
9. AI Agent and Framework Directories
10. Developer Launch Platforms
11. The llms.txt Standard
12. Submission Aggregator Services
13. The Optimal Listing Sequence

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1. The Master Table: All 50 Marketplaces Ranked by Impact/Effort

This table scores every marketplace on two dimensions. Impact (1-10) combines estimated monthly reach, audience quality (developers vs general public), and discovery value (whether listings drive ongoing traffic or just a launch spike). Effort (1-10, where 10 = easiest) combines time to list, cost, technical requirements, and approval complexity. The Score is Impact multiplied by Effort, divided by 10, producing a 1-10 ranking where high score = high impact, low effort.

The table is grouped by category. Within each category, marketplaces are ordered by Score (highest first).

MCP Server Directories

API Marketplaces (Monetization)

Integration Platforms

Cloud Marketplaces

AI Tool Directories

Free API Directories

AI Agent / Framework Directories

Launch Platforms

Standards and Aggregators

The scoring reveals a clear priority order. The top 5 listings by Score are: Official MCP Registry (9.0), Glama (8.0), Smithery (7.2), RapidAPI (7.2), and Postman API Network (7.2). These five should be every builder's first actions. They combine massive reach with fast, free, low-friction listing processes. After these five, the next tier includes the MCP community directories (mcp.so, PulseMCP), the AI tool directories (TAAFT, Toolify, Futurepedia), and the GitHub-based API lists.

For a detailed overview of how APIs and MCP servers fit into the broader AI agent tooling ecosystem, see our LLM tool gateways guide which covers the architectural layer connecting agents to external tools.

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2. Listing Categories: Programmatic, Form, and Complex

Every marketplace falls into one of three listing categories. Understanding which category a marketplace belongs to determines whether you can delegate listing to an AI coding agent, handle it yourself in 5 minutes, or need to invest hours of preparation.

Programmatic Listings (Your AI Coder Can Do This)

Programmatic listings require only CLI commands or API calls. No web forms, no manual data entry, no screenshots. An AI coding agent (Claude Code, Cursor, Windsurf) can execute these listings autonomously.

The Official MCP Registry uses mcp-publisher, a CLI tool that authenticates via GitHub, validates your server manifest, and publishes to the canonical registry. The commands are: mcp-publisher init (creates server.json), then mcp-publisher publish. The entire process takes under 5 minutes and requires only that your MCP server is published as an npm package first.

Smithery offers a similar CLI: smithery mcp publish. The command reads your server configuration, validates MCP compliance, and publishes to Smithery's directory. Like the official registry, it requires an npm package and standard MCP server structure.

Glama requires no action at all. It auto-indexes MCP servers from GitHub repositories. If your MCP server is open-source and hosted on GitHub, Glama will discover and list it automatically. You can optionally "claim" your listing afterward to manage the description and metadata.

APIs.io accepts listings via a REST API (POST to /search/apis) or by hosting an apis.json file at your domain root. This is the most API-native listing method: your domain serves a machine-readable description that APIs.io periodically crawls and indexes.

These programmatic channels are where AI coding agents add the most value. A single prompt like "list our MCP server on the official registry, Smithery, and set up apis.json" can produce three listings in under 10 minutes without any human interaction with web forms.

Form-Based Listings (5-15 Minutes Each)

Form-based listings require visiting a website, filling in fields (name, description, URL, logo), and clicking submit. They are fast but require manual browser interaction that AI coding agents cannot currently automate.

Most MCP directories fall in this category: mcp.so (Submit button or GitHub issue), PulseMCP (Submit button), mcpservers.org (web form or GitHub PR), MCP Market (web form), and MCPServerFinder (web form or email). Each takes 5 minutes if you have your metadata prepared in advance.

The AI tool directories are also form-based: There's An AI For That (form + $347 payment), Toolify.ai (form + $99), Futurepedia (form, free or $497 verified). These take slightly longer because they require crafting marketing-oriented descriptions rather than technical specifications.

Postman API Network requires creating a public workspace and adding your API collection, which takes about 15 minutes but involves more steps than a simple form.

The major AI tool directories also fall in this category. There's An AI For That, Toolify.ai, and Futurepedia all use web forms that take 10-15 minutes. The main difference is that these paid directories ($99-$497) provide guaranteed visibility (newsletter inclusion, featured placement, dofollow backlinks) that free directories cannot match. The payment is not for listing speed (which is comparable to free directories) but for promotional amplification.

A tactical note on form-based listings: the order in which you fill out fields matters for efficiency. Most forms follow a pattern: name, URL, description, category, logo, tags. If you fill these out from scratch each time, you waste time on the identical information. If you prepare a structured document with every possible field pre-written, each form becomes a copy-paste exercise.

The key optimization for form-based listings is preparing a submission template with all your metadata in one document: name, one-liner, short description, long description, website URL, documentation URL, GitHub URL, logo URL, categories, tags, and authentication details. With this template, each form-based listing becomes a 2-3 minute copy-paste operation rather than a 10-15 minute composition exercise.

Our Suprsonic MCP marketplace listings tracker documents exactly this approach, including the template we used to list across 18 marketplaces in a single day.

Complex Listings (Hours to Weeks)

Complex listings require significant preparation: building integrations, packaging code, creating test accounts, writing documentation to specific standards, and going through manual review processes.

Zapier is the most impactful complex listing. Building a Zapier integration requires using the Zapier Platform SDK, creating 10+ Zap templates, and achieving 50 active users before the integration is publicly listed - Zapier. The development effort is days to weeks, but the distribution payoff is enormous: Zapier's 8,000+ integration pages drive 2.6 million organic visitors per month, and every integration page becomes a permanent SEO asset linking back to your product.

Cloud marketplaces (AWS, Azure, Google Cloud) require the most preparation. AWS Marketplace needs tax forms, a US bank account, API Gateway integration, and Entitlement Service implementation - AWS. Azure requires Partner Center registration and SaaS fulfillment API integration. Google Cloud requires Partner Advantage Program membership and Build Partner status. Each takes weeks of preparation but unlocks enterprise procurement budgets where customers can apply committed cloud spend to your API.

Claude Desktop Extensions require packaging your MCP server as a .mcpb bundle using Anthropic's mcpb CLI, creating screenshots, writing a privacy policy, and passing a manual review. The effort is 2-4 hours of preparation plus review waiting time, but the reach (all Claude Desktop users) makes it high-impact.

The decision framework for complex listings is: pursue them only after you have exhausted all programmatic and form-based listings. The marginal impact of listing on your 15th MCP directory is lower than investing that time in one complex integration that unlocks a new distribution channel.

What Each Category Requires: A Quick Reference

Understanding what you need to prepare for each category saves time on listing day.

MCP directories require: npm package published, GitHub repository URL, MCP server manifest (server.json), installation instructions (typically npx your-package), tool descriptions with clear names and parameter schemas, and environment variable documentation for authentication.

API marketplaces require: OpenAPI/Swagger specification (preferably hosted at a stable URL like yourdomain.com/v1/openapi.json), endpoint documentation, authentication method description, pricing tiers (free tier strongly recommended for discovery), and test credentials for reviewer access.

Integration platforms require: Full integration code built on the platform's SDK (Zapier Platform SDK, Make app connector, n8n node package), trigger and action definitions mapped to your API endpoints, test accounts for the review team, and often 10+ example automation templates.

AI tool directories require: Product name, website URL, one-paragraph description focused on user benefit (not technical specs), logo image, category selection, and often a payment of $99-$497.

Cloud marketplaces require: Business entity registration, tax documentation (W-9 for US sellers), bank account for payouts, API Gateway or fulfillment API integration, compliance documentation, and often a partnership agreement.

The preparation gradient is steep. MCP and API directories need technical artifacts you already have (npm package, OpenAPI spec, GitHub repo). Integration platforms need custom development work. Cloud marketplaces need business and legal documentation. Planning your listing campaign around this gradient ensures you handle the easiest, highest-impact listings first.

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3. MCP Server Directories (The First 10 You Should List On)

MCP (Model Context Protocol) directories are the most important distribution channel for tool builders in 2026 because they are where AI agents discover tools. Unlike traditional API directories (which humans browse), MCP directories are increasingly queried programmatically by agent platforms. When a user asks Claude Desktop to "find a tool that can search the web," Claude checks the MCP registry and marketplace for matching servers. Being listed in these directories is not just about human discovery. It is about machine discovery.

Official MCP Registry (List Here First)

The Official MCP Registry at registry.modelcontextprotocol.io is the canonical source. All major MCP clients (Claude Desktop, Cursor, VS Code MCP extension, custom agent frameworks) check this registry for available servers. Listing here is the single highest-impact action you can take because it cascades to downstream directories that auto-index from the official registry.

The listing process is fully programmatic. Install the mcp-publisher CLI, run mcp-publisher init to generate a server.json manifest describing your server, then run mcp-publisher publish to authenticate via GitHub and push to the registry. Your MCP server must be published as an npm package first. The entire process takes under 10 minutes.

Once published to the Official Registry, your listing automatically appears in several downstream directories: the GitHub MCP Registry (which VS Code and other IDEs check), Glama (which maintains a superset of the official registry), and PulseMCP (which ingests from the official registry weekly). This cascading effect means one listing produces three or four additional listings automatically.

Glama: Largest Auto-Indexed Directory

Glama at glama.ai/mcp/servers indexes 21,949 open-source MCP servers and receives approximately 82,000 monthly visits - Glama. It auto-indexes from GitHub, meaning if your MCP server is in a public GitHub repository, Glama will find and list it without any action from you.

Glama provides an in-browser MCP inspector that lets potential users test your tools without installing anything. This test-before-install capability significantly reduces adoption friction. Glama also provides quality/safety scoring and maintainer verification, which helps established servers stand out from abandoned or low-quality entries.

Smithery: Marketplace with Hosting

Smithery at smithery.ai hosts 7,000+ servers and differentiates from pure directories by offering hosted/remote MCP deployment. When you list on Smithery, users can run your MCP server on Smithery's infrastructure rather than installing it locally. This is significant for MCP servers that require complex dependencies, environment variables, or compute resources that are inconvenient to set up locally.

The listing process uses the smithery mcp publish CLI command or a web dashboard. Smithery also accepts GitHub PRs for listing. The built-in install command (smithery install your-server) provides a one-click installation experience for users.

The Cascading Effect: One Listing Creates Many

A critical insight from our listing experience is that the MCP directory ecosystem has a cascading architecture. Publishing to the Official MCP Registry automatically propagates your listing to at least three downstream directories: the GitHub MCP Registry (which IDEs like VS Code check), Glama (which maintains a superset of the official registry and adds quality scoring), and PulseMCP (which ingests from the official registry on a weekly cycle). Several other directories, including Claude's integrated marketplace and various community aggregators, also auto-index from upstream sources.

This means the effective reach of listing on the Official MCP Registry is not just the registry itself, but the combined audience of every downstream directory that auto-indexes from it. We documented this cascading effect when listing Suprsonic's MCP server: one mcp-publisher publish command resulted in the server appearing in four directories within 48 hours without any additional action.

The practical implication is that listing order matters. Always list on upstream directories (Official Registry) before downstream ones (specific community directories), because the upstream listing may auto-populate the downstream directory, saving you the manual submission step. If you list on a downstream directory first and then the upstream auto-populates, you may end up with duplicate listings that need to be reconciled.

Reach Estimation for MCP Directories

Most MCP directories do not publish traffic data, making impact assessment difficult. Based on available data and reasonable inference:

The Official MCP Registry has no published traffic numbers, but its impact is multiplicative because every MCP-compatible client (Claude Desktop with 100M+ potential users, Cursor with millions of developers, VS Code extensions) checks this registry. The effective reach is bounded not by the registry's website traffic but by the install base of MCP-compatible clients.

Glama receives approximately 82,000 monthly visits based on available analytics data, plus additional programmatic queries from tools that use Glama's API for MCP server discovery. Smithery does not publish traffic but its 7,000+ servers and active community suggest comparable engagement. mcp.so and PulseMCP are community directories with lower but growing traffic that collectively represent the long tail of MCP discovery.

For a comprehensive overview of the MCP ecosystem and how these directories connect to agent platforms, see our 50 best MCP servers guide which covers the consumer side of MCP discovery.

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4. API Marketplaces with Monetization

If your goal is not just discovery but revenue, four marketplaces offer built-in monetization: billing, subscription management, and payment processing handled by the platform.

RapidAPI: Largest API Marketplace

RapidAPI at rapidapi.com serves 3 million+ registered developers with 10,000+ APIs listed. It is the largest API marketplace by developer reach and the default discovery channel for developers searching for API services - RapidAPI. RapidAPI recently added MCP server support, making it relevant for both traditional API and MCP distribution.

Listing on RapidAPI takes about 15 minutes. Navigate to RapidAPI Studio, create an API project, import your OpenAPI spec (or manually define endpoints), set pricing tiers (a free tier is strongly recommended for discovery), and toggle the project to public. No editorial review is required for basic listing. Your API goes live immediately.

RapidAPI handles billing, API key management, rate limiting, and analytics. The commission structure is 25% of all revenue plus 2.9% + $0.30 per transaction. Payouts are via PayPal only. The 25% commission is the highest among API marketplaces but is offset by the massive developer audience. For API builders who would otherwise need to build their own billing infrastructure, the commission is effectively the price of a managed monetization platform.

Postman API Network: Largest Developer Hub

Postman API Network at postman.com/explore is the world's largest public API hub with 30 million+ registered developers and 100,000+ public APIs - Postman. Listing is free, has no commission structure, and provides massive SEO value because Postman's domain authority ensures your API listing ranks well in search results.

To list, create a public Postman workspace, add your API collection (either imported from OpenAPI spec or built manually), write documentation within Postman, and make the workspace public. The process takes about 15 minutes. There is no editorial review for basic listings, though featured placement requires Postman team outreach.

Postman does not handle monetization. It is a pure discovery and documentation platform. Developers find your API through Postman, test it using Postman's built-in tools, and then integrate it using your own authentication and billing. For APIs that already have their own billing (like those built on Suprsonic infrastructure), Postman provides high-quality discovery without revenue share.

In March 2026, Postman launched an AI-native platform rebuild that positions collections as AI-consumable tool definitions. This evolution means Postman API Network listings are becoming discoverable not just by human developers browsing the network, but by AI agents that query the network for tool capabilities. For API builders, this means a Postman listing now serves double duty: human discovery through the web interface and machine discovery through Postman's AI integration.

API Market: Emerging Contender

API Market at api.market/seller is a newer marketplace that lists 300+ APIs serving 10,000+ developers across 50+ countries. It supports both traditional REST APIs and MCP servers, making it one of the few platforms that serves both distribution channels from a single listing.

The self-service dashboard handles billing, authentication, rate limiting, and analytics. The commission structure is not publicly disclosed but is reportedly competitive with APILayer (lower than RapidAPI's 25%). The platform provides 24/7 support for listed providers, which is unusual for a marketplace of this size and suggests investment in provider experience.

For API builders who want monetization without RapidAPI's 25% commission but lack the developer base to justify enterprise cloud marketplace integration, API Market occupies a useful middle ground. The trade-off is smaller reach: 10,000 developers is significant for a young marketplace but modest compared to RapidAPI's 3 million.

APILayer: Curated Quality

APILayer at marketplace.apilayer.com takes a deliberately different approach: only 75+ curated APIs are listed, hand-selected for quality in each category. The commission is 15% (lowest among monetization marketplaces), and the curation means less competition per category - APILayer.

The trade-off is that listing requires an application and manual review. APILayer rejects APIs that duplicate existing categories or do not meet their quality bar. Requirements include a REST API hosted on a major cloud provider, sample requests/responses, documented use cases, and load balancer setup. Monthly payouts are available for providers.

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5. Integration Platforms (Zapier, Make, n8n, Pipedream)

Integration platforms represent the highest-impact, highest-effort listings. A Zapier integration reaches 2.6 million monthly organic visitors and creates permanent SEO-optimized pages, but building the integration takes days to weeks. These listings are worth the investment for APIs with broad use cases, but the effort threshold makes them impractical for niche tools.

Zapier: Maximum Distribution, Maximum Effort

Zapier at zapier.com/developer-platform is the gold standard for API distribution. Every Zapier integration creates dedicated pages (/apps/your-tool) that rank in Google for " [your tool] + [other tool] integration" searches. These pages drive 235,000 monthly visitors collectively - Zapier.

Building a Zapier integration requires the Zapier Platform SDK, creating triggers, actions, and searches that map to your API endpoints, plus building 10+ Zap templates that demonstrate common use cases. The public listing requirement is 50 active users (users who have your integration in an active Zap), though this can be waived for integrations embedded within your own product.

The review process is manual, with a 4-tier partner program (evaluated quarterly based on active users and integration health score). The investment is significant, but no other single listing provides comparable ongoing distribution.

The 50-user requirement is the primary barrier to entry. For new APIs without an existing user base, achieving 50 active Zapier users before public listing seems like a chicken-and-egg problem. The workaround is embedding Zapier within your own product: if your API's documentation or dashboard includes Zapier templates that users can activate, these count toward the 50-user threshold. Several API builders have reached the threshold by creating 3-5 high-value Zap templates and promoting them in their onboarding flow, converting existing API users into Zapier integration users.

The SEO value of a Zapier listing deserves emphasis because it is the most durable benefit. Every Zapier integration creates pages like zapier.com/apps/your-tool/integrations/google-sheets for every possible integration pairing. If your tool has Zapier triggers and actions, it generates hundreds of combination pages that rank for long-tail searches like "connect [your tool] to [other tool]." These pages drive organic traffic for years after the initial integration launch, making Zapier one of the few platforms where the listing's value increases over time rather than decaying.

n8n Community Nodes: Open Source Distribution

n8n at docs.n8n.io offers the most developer-friendly integration platform listing. Publish your node as an npm package with the n8n-nodes- prefix and submit for verification via the Creator Portal. The open-source community has produced 5,834 community nodes growing at approximately 13.6 per day.

Starting May 2026, n8n requires GitHub Actions with a provenance statement for new community node submissions, adding a security verification layer. The community directories at ncnodes.com, n8engine.com, and awesome-n8n provide additional discovery channels for listed nodes.

Make.com: Enterprise Integration Distribution

Make.com (formerly Integromat) at f.make.com/submit-your-app hosts 3,000+ integrations and serves a strong enterprise and SMB audience. The listing process involves building a Make app connector, completing a review, signing a partner agreement, and going through an onboarding call with the Make team.

The onboarding call is unique among integration platforms. Make pairs new partners with an integration specialist who helps optimize the connector for their marketplace, suggests Zap-equivalent templates, and provides guidance on maximizing discovery within Make's ecosystem. This white-glove approach means more effort upfront but higher-quality listings that perform better.

Make recently launched a beta marketplace program for app monetization, allowing integration providers to charge users directly through the Make platform. This positions Make as a direct competitor to RapidAPI for API monetization, though the user base is smaller.

Pipedream: Developer-Friendly Open Source

Pipedream at pipedream.com/docs/apps/contributing takes a fully open-source approach. Contributing requires forking the Pipedream GitHub repository, adding your component to the app directory following their framework conventions, and submitting a pull request. The Pipedream components team reviews PRs and provides feedback.

Pipedream's event-driven architecture differentiates it from Zapier and Make. Rather than polling-based triggers, Pipedream components can respond to webhook events in real time, making it particularly suitable for APIs that produce real-time data streams or event notifications. For API builders whose tools are naturally event-driven (monitoring alerts, data change notifications, incoming messages), Pipedream's architecture provides a more natural integration model.

For our guide on building MCP servers that can serve as the foundation for integration platform listings, see our build your first MCP server guide.

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6. Cloud Marketplaces (AWS, Azure, Google Cloud)

Cloud marketplaces are the enterprise distribution channel. They provide access to corporate procurement budgets, committed cloud spend, and enterprise buyers who prefer purchasing through their existing cloud vendor relationship. The trade-off is extreme: listing on any cloud marketplace requires weeks of preparation, complex technical integration, and ongoing compliance maintenance.

AWS Marketplace charges a 3% transaction fee on deals under $1M (scaling down to 1.5% above $10M) and requires tax forms, a US bank account, and API Gateway integration for API-based products - AWS. The Catalog API enables programmatic listing creation.

Azure Marketplace charges a 3% store service fee and requires Partner Center registration and SaaS fulfillment API integration. The Product Ingestion API enables programmatic listing management. Azure recently added AI Apps/Agents as a category, making it relevant for AI tool builders.

Google Cloud Marketplace charges a 3% revenue share and requires Partner Advantage Program membership at Build Partner level. The Cloud Commerce Partner Procurement API handles integration. Requirements include production-ready status (no alpha/beta), enterprise readiness, and primary hosting on Google Cloud.

All three cloud marketplaces share a critical benefit: customers can apply committed cloud spend to purchases. This means an enterprise customer with $1M in unused AWS credits can effectively get your API for "free" from their budget perspective, dramatically reducing purchase friction. This procurement mechanism is why cloud marketplace deals often close faster and with less friction than direct sales: the budget already exists and is allocated, and the customer does not need to go through a new vendor approval process.

The programmatic listing capabilities deserve attention for API builders who want to automate their marketplace presence. AWS Catalog API enables creating and updating listings programmatically, meaning your CI/CD pipeline can automatically update your marketplace listing when you release a new API version. Azure Product Ingestion API provides similar capabilities for the Microsoft ecosystem. These APIs mean that marketplace listing maintenance can be fully automated, reducing the ongoing overhead from hours per update to zero.

A recent development worth noting: Azure added a new AI Apps/Agents category specifically for AI tools and agent services. This category has lower competition than established software categories and receives promotional attention from Microsoft as they position Azure as the AI development platform. For AI-focused API builders, listing in this new category provides early-mover advantage with category-specific visibility.

For most API builders, cloud marketplace listings should be pursued only after organic growth has validated product-market fit and enterprise demand exists. The preparation effort is too high for tools that are still finding their audience.

The commission comparison reveals an important economic insight. Cloud marketplaces charge dramatically less (3%) than API-specific marketplaces (15-25%) because their business model is built on cloud infrastructure consumption, not marketplace fees. API marketplace commissions include billing infrastructure, developer portal hosting, and API key management that cloud marketplaces do not provide. For API builders who have their own billing infrastructure, cloud marketplaces offer the most cost-efficient monetization. For builders who need end-to-end billing management, the higher API marketplace commissions include services that would otherwise cost $500-$2,000/month to build and maintain independently.

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7. AI Tool Directories

AI tool directories provide the fastest path to consumer visibility. They attract millions of visitors looking for AI-powered solutions, and listing is typically a simple form submission.

There's An AI For That (TAAFT)

TAAFT at theresanaiforthat.com/launch is the #1 AI tools website with 4-7.8 million monthly visits and 1.2 million+ newsletter subscribers - TAAFT. The $347 submission fee is a one-time payment (refunded if rejected). Listings never expire, guaranteed newsletter inclusion, and typically drive hundreds of targeted visitors in the first week.

Toolify.ai

Toolify.ai at toolify.ai/submit lists 26,000+ tools across 450+ categories for a $99 submission fee. Listings appear in the "Just Launched" section within 48 hours. Toolify provides 6+ dofollow backlinks, making it one of the most SEO-valuable paid listings.

Futurepedia

Futurepedia at futurepedia.io/submit-tool reaches 400,000+ monthly visitors. Free basic listings are available, with a $497 verified listing option that includes editorial review, a credibility badge, and $1,000+ in promotional benefits. The verified listing is worth considering for APIs that benefit from third-party credibility signals.

The Paid vs Free Directory Decision

The paid AI directories (TAAFT at $347, Toolify at $99, Futurepedia at $497 for verified) raise a natural question: is the paid listing worth it compared to free alternatives?

The answer depends on your growth stage and target audience. For API and MCP builders targeting AI-focused audiences (developers building agents, automation engineers, AI startup founders), the paid directories provide concentrated exposure to exactly these audiences. TAAFT's 1.2 million newsletter subscribers alone justify the $347 fee if even 0.1% convert to API users (that is 1,200 potential users from a single listing).

For API builders targeting general developers (not specifically AI-focused), the paid AI directories provide less relevant traffic. The free API directories (Public APIs on GitHub, APIs.guru, Postman) reach developers who are searching for specific API functionality rather than browsing AI tool collections.

The optimal approach for most builders is to list on all free directories first (zero cost, 30-45 minutes total), then invest in one paid AI directory as a test ($99 for Toolify is the lowest barrier). If the Toolify listing drives measurable signups, proceed to TAAFT ($347) and Futurepedia ($497). If Toolify produces no measurable impact, the AI tool directory audience may not align with your product, and budget is better spent on developer-specific channels like Product Hunt or Zapier integration development.

Our earlier guide on where to list your API or MCP server covers additional listing strategies beyond the marketplaces covered here.

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8. Free API Directories (SEO Value)

Free API directories individually drive modest traffic, but collectively they provide significant SEO value through backlinks and cross-referencing. The effort per listing is minimal (5 minutes each), making the aggregate ROI positive even if no single directory drives meaningful direct traffic.

Public APIs (GitHub): 300K+ Stars

The public-apis GitHub repository at github.com/public-apis/public-apis has 300,000+ stars, making it one of the most popular repositories on GitHub. Listing requires a pull request following their contribution template. Your API must have a free tier. The backlink from this repository carries significant SEO weight due to GitHub's domain authority.

Patchbay: ProgrammableWeb's Replacement

Patchbay at patchbay.cc/submit was built specifically as the replacement for ProgrammableWeb (which shut down). It lists 3,100+ APIs across 56 categories with automated liveness checks that detect dead links, domain changes, and HTTPS downgrades. Patchbay also auto-imports APIs via a weekly GitHub cron job that scans for public OpenAPI specifications, meaning well-structured API projects may get listed automatically.

APIs.guru: The Wikipedia for APIs

APIs.guru at apis.guru/add-api maintains 2,337 API definitions and serves as an aggregation point that other directories reference. Submit by providing a URL to your machine-readable API definition (OpenAPI, Swagger, RAML, or API Blueprint). APIs.guru auto-updates definitions from the source URL, meaning your listing stays current without maintenance.

The SEO Multiplier Effect

The collective SEO value of listing on multiple free directories is greater than the sum of individual listings. Each directory that links to your API creates a backlink from a domain with existing authority. Google's algorithm weights backlink diversity (links from many different domains) higher than link volume from a single domain. Listing on 10 free directories produces 10 backlinks from 10 different domains, each reinforcing your API's authority for searches like " [your category] API" or " [your use case] tool."

The SEO multiplier is particularly strong for API directories because they tend to be well-structured, category-organized websites that search engines crawl regularly. A listing on APIs.guru, Patchbay, and PublicAPIs.io produces three high-quality, contextually relevant backlinks that collectively improve your ranking for API-related searches more than any single backlink would.

The time investment is minimal: 5-10 minutes per directory, 30-45 minutes total for all six free directories listed above. The SEO benefit compounds over months as search engines crawl and index the listings. For API builders who depend on organic search for developer acquisition, this 45-minute investment produces one of the highest long-term ROI activities available.

For guidance on creating the OpenAPI specification that several of these directories require, our top 10 Suprsonic alternatives guide covers how unified API platforms handle specification management.

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9. AI Agent and Framework Directories

These directories target builders who are integrating tools into AI agent frameworks. The audience is smaller but more technically engaged and more likely to integrate your tool into production systems.

OpenAI GPT Store

The GPT Store at chatgpt.com/gpts reaches hundreds of millions of ChatGPT users. Building a custom GPT that wraps your API takes about 30 minutes using ChatGPT's builder interface. The listing is free but requires a ChatGPT Plus, Team, or Enterprise subscription. The consumer reach is unmatched, but conversion to API usage depends on the GPT effectively demonstrating your API's value.

OpenAI transitioned from the earlier plugin model to the GPT Store, and in December 2025 launched a full Apps SDK and App Directory that provides deeper integration capabilities. For API builders, the GPT route is the fastest path to ChatGPT distribution: create a GPT, configure Actions that call your API endpoints, write instructions explaining when to use each action, and publish to the store. The GPT functions as a demo and distribution channel simultaneously: users interact with your API through the GPT's conversational interface, experience its value, and then integrate the API directly into their own workflows.

The conversion funnel from GPT Store to direct API usage is indirect but measurable. Users who discover your capabilities through a GPT and find them valuable will search for your API independently. This is why the GPT's name and description should clearly state your product name and direct API availability, not just describe the GPT's functionality. A GPT named "Web Search Pro" powered by your API teaches users nothing about where to find the underlying API. A GPT named "Suprsonic Web Search" with a description mentioning the Suprsonic API creates a discoverable connection.

LangChain Integrations

LangChain at github.com/langchain-ai/langchain has 1,000+ integrations and is the most widely used AI agent framework. Contributing a LangChain integration (via PR to the langchain-community repository) makes your tool available to the entire LangChain/LangGraph ecosystem. The effort is hours (building a Python tool class following LangChain's interface), but the distribution is high-quality: developers who find your tool through LangChain are specifically building agent systems that need tools.

Composio: AI Agent Tool Platform

Composio at composio.dev connects 500+ apps with 1,000+ toolkits and 20,000+ individual tools accessible to AI agents. Composio's differentiation is handling the authentication layer: it manages OAuth flows, API key rotation, and token refresh for connected services, meaning agent builders can focus on tool logic rather than auth infrastructure.

Listing on Composio typically requires a platform partnership or integration agreement. The effort is moderate (hours, not weeks) but involves alignment with Composio's tool interface standards. The benefit is that Composio provides MCP server support at mcp.composio.dev, meaning your tool becomes available to both Composio's native agent ecosystem and any MCP-compatible client.

For API builders whose tools require user-level authentication (OAuth for services like Gmail, Slack, Salesforce), Composio handles the OAuth complexity that would otherwise require significant development. This makes Composio particularly valuable for tools that need to act on behalf of specific users rather than just processing requests with a service-level API key.

Apify Store

The Apify Store at apify.com/store hosts 20,000+ actors with a combined 890,000+ users. Building an Apify actor wrapping your API takes a few hours but provides usage-based monetization (users pay per event, you earn revenue) and a ready-made marketplace of automation-focused users. The store API enables programmatic listing management - Apify.

The Apify Store has a distinct advantage for data-focused APIs (scraping, enrichment, search, extraction): its user base is specifically looking for data automation tools. An API listed on Apify reaches users who are actively building data pipelines, web scrapers, and automation workflows. This audience-product fit means lower listing volume but higher conversion rates compared to general-purpose API directories.

LangChain and CrewAI: Framework-Native Distribution

Being listed as a LangChain integration carries significant weight in the AI agent developer community because LangChain is the most widely used framework for building agents. A LangChain-native tool can be imported with a single from langchain_community.tools import YourTool statement, which dramatically reduces the integration friction for developers who are already building on LangChain.

Contributing requires implementing the LangChain tool interface (a Python class with _run and _arun methods), writing documentation following LangChain's standards, adding tests, and submitting a PR to the langchain-community repository. The development effort is hours, and the PR review process typically takes 1-2 weeks. Once merged, your tool appears in LangChain's documentation, is installable via pip, and becomes part of every LangChain installation.

CrewAI Marketplace at marketplace.crewai.com targets enterprise users who deploy multi-agent systems. The marketplace is more selective (submit for evaluation rather than self-publish), but reaching enterprise AI agent deployments justifies the higher effort for tools that serve enterprise use cases.

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10. Developer Launch Platforms

Launch platforms drive spike traffic rather than ongoing discovery. They are best used for initial launches or major updates, not as persistent distribution channels.

Product Hunt

Product Hunt at producthunt.com drives 4.5-8.3 million monthly visits with 20.75% of its audience in programming/developer software. A well-executed launch can drive 3-5x normal signup rates on launch day. Key tactics: launch at 12:01 AM PST, coordinate with email list and social channels, prepare high-quality assets (logo, video, screenshots), and engage with comments throughout the day.

Product Hunt's algorithm weights quality of engagement over raw upvotes, meaning a smaller but genuinely engaged audience produces better results than vote-buying schemes. The launch day spike is significant but temporary; the lasting value is the permanent Product Hunt listing that provides a credibility signal and backlink.

The timing of your Product Hunt launch relative to your marketplace listings matters. Launch on Product Hunt after you have completed all directory listings, so that visitors from the Product Hunt spike find your API listed across multiple platforms (reinforcing credibility) and can discover your tool through whichever channel they prefer (Postman, RapidAPI, MCP registry, etc.). Launching on Product Hunt before listing elsewhere wastes the spike traffic on visitors who cannot find your tool anywhere besides your own website.

DevHunt

DevHunt at devhunt.org positions itself as "Product Hunt for developer tools." GitHub-verified voting prevents spam and provides stronger signal quality than Product Hunt's more general audience. Limited weekly launch slots create scarcity that increases per-listing visibility. The developer-only focus means every visitor is in your target audience.

Launch Platform Strategy: Timing and Coordination

The most common mistake with launch platforms is treating them as one-off events rather than coordinated campaigns. A Product Hunt launch without supporting promotion reaches only Product Hunt's organic audience. A coordinated launch, where you notify your email list, post on social media, message relevant communities, and ping partners for support, amplifies the spike by 3-5x.

The timing consideration is specific: Product Hunt resets its daily rankings at 12:01 AM PST. Launching at this exact time gives you the maximum window to accumulate upvotes during the 24-hour ranking period. Late launches (afternoon PST) compete for fewer remaining hours and consistently underperform morning launches.

DevHunt's limited weekly launch slots create natural scarcity. Because fewer tools launch per week, each launch receives proportionally more visibility. For developer tools that might get lost in Product Hunt's broader audience (which includes consumer products, design tools, and non-technical products), DevHunt's focused audience provides better signal quality per impression.

The optimal sequence is: complete all directory listings first (Day 1 and Week 1 from the listing sequence), then launch on Product Hunt in Week 2. This ensures that visitors from the launch spike find your API listed across multiple platforms, reinforcing credibility and providing multiple discovery paths for users who prefer different platforms.

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11. The llms.txt Standard

llms.txt is not a marketplace but an emerging web standard that complements marketplace listings. By placing a /llms.txt file at your domain root, you provide a curated, markdown-formatted description of your API that LLMs can read during inference time - llmstxt.org.

The specification (version 1.1.1), proposed by Jeremy Howard of Answer.AI, coexists with robots.txt and sitemaps. Documentation tools like Mintlify and Fern support auto-generating llms.txt from existing API documentation. No major AI provider has publicly confirmed parsing llms.txt files during inference, but the standard is gaining adoption as a low-effort hedge: creating the file takes 10 minutes, costs nothing, and positions your API for discoverability if LLM providers adopt the standard.

The practical implementation is straightforward: create a markdown file listing your API's key pages (documentation, guides, examples) in priority order, and serve it at yourdomain.com/llms.txt. Tools like Suprsonic already serve an llms.txt file alongside their OpenAPI spec, providing both machine-readable API definitions and LLM-readable documentation at standard endpoints.

The relationship between llms.txt and MCP directories deserves consideration. MCP directories enable agents to discover and use your tools at runtime. llms.txt enables LLMs to understand your tools during inference time (when they are generating responses to user queries). These are complementary channels: an LLM that reads your llms.txt might recommend your API in its response, while an agent that discovers your MCP server through a registry uses it directly. Together, they cover both the recommendation and integration pathways.

The content of your llms.txt should be concise and structured for LLM consumption, not human browsing. List your most important pages first (API documentation root, quickstart guide, pricing, authentication). Include brief annotations explaining what each page contains. Avoid marketing language; LLMs parse informational content more effectively than persuasive copy. A well-structured llms.txt file should be 20-50 lines, not hundreds.

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12. Submission Aggregator Services

For builders who want to maximize directory coverage without manually visiting 50 websites, aggregator services submit your tool to multiple directories in one action.

Submit a Tool at submitatool.com submits your AI tool to 270+ directories in a single process. This brute-force approach saves hours of manual form-filling but provides less control over individual listing descriptions and metadata.

Launch Directories at launchdirectories.com provides a curated list of directories organized by type, with submission guides for each. Rather than submitting for you, it organizes the information you need to submit yourself, which provides more control over listing quality.

The best-of-ai/ai-directories GitHub repository at github.com/best-of-ai/ai-directories maintains a curated list of AI directories, serving as a meta-directory for discovering additional listing opportunities beyond the 50 covered in this guide.

Aggregator services work best for AI tool directories (where listings are simple name/URL/description forms) and less well for technical directories (which require specific artifacts like OpenAPI specs, npm packages, or MCP manifests). For the technical directories in this guide, manual or programmatic listing is still the most reliable approach because aggregators cannot provide the specialized artifacts each platform requires.

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13. The Optimal Listing Sequence

Based on the Impact/Effort scoring and our experience listing across 18 marketplaces in a single day, here is the optimal sequence for a new API or MCP server launch.

Day 1: High-Impact Programmatic (2 hours total)

List on every platform that can be done programmatically or via quick form submission. These 10 listings take approximately 2 hours total and cover the highest-impact channels.

Step 1 (10 min): Publish npm package with your MCP server. This is a prerequisite for registry listings.

Step 2 (10 min): Publish to Official MCP Registry via mcp-publisher. This cascades to Glama, PulseMCP, and GitHub MCP Registry automatically.

Step 3 (10 min): Publish to Smithery via smithery mcp publish.

Step 4 (5 min each, 25 min total): Submit to mcp.so, PulseMCP, mcpservers.org, MCP Market, MCPServerFinder via web forms.

Step 5 (15 min): Create Postman public workspace with your API collection.

Step 6 (15 min): List on RapidAPI via OpenAPI import.

Step 7 (5 min each, 25 min total): Submit to APIs.guru, Patchbay, PublicAPIs.io, APIList.fun, publicapis.dev via web forms.

Step 8 (10 min): Submit PR to public-apis GitHub repository.

Week 1: Paid AI Directories (30 minutes + budget)

Step 9 ($99, 10 min): Submit to Toolify.ai.

Step 10 ($347, 10 min): Submit to There's An AI For That.

Step 11 (Free or $497, 10 min): Submit to Futurepedia.

Week 2: Launch Event

Step 12 (1-2 hours): Launch on Product Hunt (coordinate with email, social, PR).

Step 13 (15 min): Launch on DevHunt.

Month 1: Complex Integrations

Step 14 (2-4 hours): Package and submit Claude Desktop Extension.

Step 15 (30 min): Build and publish OpenAI GPT wrapping your API.

Step 16 (Days): Begin Zapier integration development if applicable.

Step 17 (10 min): Set up llms.txt at your domain root.

Step 17b (15 min): Submit to Cursor Directory and Cursor Marketplace (requires mcp.json and plugin.json in your GitHub repo).

Step 17c (10 min each): Submit to remaining AI agent directories: AI Agent Store, AI Agents Directory, TrillionAgent.

Month 2-3: Enterprise and Framework

Step 18 (Hours): Contribute LangChain integration.

Step 19 (Hours): Build and publish Apify actor.

Step 20 (Weeks): Pursue cloud marketplace listings if enterprise demand warrants.

This sequence is ordered by Impact/Effort ratio: the first actions produce the most distribution value for the least work. Each subsequent step has diminishing returns on effort but adds incremental distribution. Most builders will see 80% of their distribution value from the Day 1 and Week 1 actions. The remaining 20% of distribution comes from Month 1-3 actions, which require significantly more investment per marginal user. This 80/20 distribution mirrors the Pareto principle that applies across most marketing channels.

The pyramid visualization makes the strategy clear: invest the majority of your time in the top layers (which produce the majority of distribution value) and only descend to lower layers when you have capacity and market validation. Most API and MCP builders never need to reach the bottom layer (cloud marketplaces) because the upper layers provide sufficient distribution for their growth stage.

What to Prepare Before You Start Listing

Before executing the listing sequence, prepare a submission kit that contains everything any marketplace might ask for. Having this kit ready turns each listing from a 15-minute composition exercise into a 2-minute copy-paste operation.

Your submission kit should contain: Product name (consistent across all platforms). One-line tagline (under 100 characters, captures what your API does). Short description (2-3 sentences, for directory cards). Long description (2-3 paragraphs, for full listing pages). Website URL. Documentation URL. GitHub repository URL (required for most MCP directories). npm package name (required for MCP registry listings). OpenAPI specification URL (required for RapidAPI, APIs.guru, Postman, Patchbay). Logo image URL (hosted on your domain, minimum 256x256px, ideally SVG or high-res PNG). Screenshot images (3-5 product screenshots for directories that support them, 1000px+ width). Category and tags (5-10 relevant keywords). Authentication details (API key format, env variable name, how to obtain). Server configuration JSON (for MCP listings: the claude_desktop_config.json snippet). Contact email (for platforms that require a maintainer contact). Privacy policy URL (required for Claude Desktop Extensions and some app stores).

With this kit prepared, the Day 1 listing sequence of 20+ submissions becomes a straightforward process of visiting each URL, pasting the appropriate fields, and clicking submit. Without the kit, each submission requires composing descriptions on the fly, which is slower and produces inconsistent messaging across platforms.

Measuring Listing Impact

After listing, track which marketplaces actually drive discovery and integration. The metrics that matter are:

Direct signups: How many new API users attribute their discovery to a marketplace listing? A post-signup survey question ("How did you hear about us?") with marketplace options provides the clearest attribution, though self-reported attribution is inherently noisy.

Referral traffic: Which marketplace URLs appear in your analytics as referral sources? Postman and RapidAPI typically drive the most measurable traffic. MCP directories drive traffic that is harder to attribute because discovery often happens inside IDE clients rather than web browsers.

API key creation: For APIs that issue keys, track which keys are created from marketplace-referred sessions. This measures actual integration intent, not just curiosity.

npm install counts: For MCP servers, npm info your-package shows weekly download counts. Spikes after listing on a specific directory indicate that directory's discovery impact.

Backlink monitoring: Tools like Ahrefs or Google Search Console show when new backlinks from directory listings are indexed, and the impact on your search ranking for relevant keywords.

The expected pattern is that the top-5 marketplaces (Official MCP Registry, RapidAPI, Postman, TAAFT, and Toolify) drive 80%+ of measurable impact, while the remaining 45 directories contribute incremental SEO value and long-tail discovery. This validates the prioritized listing sequence: invest heavily in the top tier, then distribute remaining effort across the long tail.

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This guide reflects the API and MCP marketplace landscape as of April 2026. Submission URLs, requirements, pricing, and reach estimates change frequently. Verify current details on each platform before submitting. Reach estimates for platforms without public traffic data are based on listed item counts, community engagement signals, and available SimilarWeb data. New MCP directories and AI tool marketplaces are launching regularly as the ecosystem matures, so check for new entrants that may have emerged after this guide was published.