OpenAPI.city - Stop AI agents from hallucinating APIs

Your AI agent queries openapi.city and gets exactly what it needs — a single endpoint, a schema, or a compact summary. No manual spec hunting.

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    <div class="font-mono text-xs font-semibold text-primary bg-primary/10 inline-flex items-center justify-center w-8 h-8 rounded-lg mb-5">01</div>
    <h3 class="text-lg font-semibold mb-2">Find an API</h3>
    <p class="text-sm text-base-content/50 leading-relaxed">Search across 100+ indexed providers. Filter by category, tag, or keyword. Get structured results instantly.</p>
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    <div class="font-mono text-xs font-semibold text-primary bg-primary/10 inline-flex items-center justify-center w-8 h-8 rounded-lg mb-5">02</div>
    <h3 class="text-lg font-semibold mb-2">Get what you need</h3>
    <p class="text-sm text-base-content/50 leading-relaxed">Request a single endpoint, a tag group, or an AI-optimized summary. Nested schemas available on-demand via <code class="text-primary/70 bg-primary/10 px-1 rounded text-xs">get_schemas</code> — lean responses, no bloat.</p>
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    <h3 class="text-lg font-semibold mb-2">Ship the integration</h3>
    <p class="text-sm text-base-content/50 leading-relaxed">Your agent has auth requirements, parameters, request/response schemas, and base URLs. Enough context to write working code.</p>
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      <span class="font-mono text-sm font-semibold">REST API</span>
      <span class="font-mono text-xs px-2 py-0.5 rounded bg-primary/10 text-primary font-medium">GET</span>
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      <span class="text-base-content/30"># Get a single endpoint with resolved schemas</span><br><br>
      GET /api/v1/providers/stripe/endpoints/<br>
      &nbsp;&nbsp;&nbsp;&nbsp;POST/charges<br><br>
      Authorization: Bearer oac_live_...<br><br>
      <span class="text-base-content/30"># Response: parameters, request body,</span><br>
      <span class="text-base-content/30"># response schemas (refs to schemas)</span>
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      <span class="font-mono text-sm font-semibold">MCP Server</span>
      <span class="font-mono text-xs px-2 py-0.5 rounded bg-primary/10 text-primary font-medium">POST</span>
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    <div class="p-5 font-mono text-sm leading-8 text-base-content/50">
      <span class="text-base-content/30"># List Slack endpoints via MCP tool</span><br><br>
      {<br>
      &nbsp;&nbsp;"name": "list_endpoints",<br>
      &nbsp;&nbsp;"arguments": {<br>
      &nbsp;&nbsp;&nbsp;&nbsp;"provider": "slack",<br>
      &nbsp;&nbsp;&nbsp;&nbsp;"tag": "chat"<br>
      &nbsp;&nbsp;}<br>
      }<br><br>
      <span class="text-base-content/30"># Returns structured endpoint list</span>
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    <div class="collapse-title text-base font-semibold">What is openapi.city?</div>
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      An API spec index and delivery service built for AI agents. We parse, resolve, and host OpenAPI specifications so your agent can query exactly what it needs — a single endpoint, a compact summary, or a full schema — without dumping entire specs into the context window.
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    <div class="collapse-title text-base font-semibold">What's the difference between context7 and openapi.city?</div>
    <div class="collapse-content text-sm text-base-content/60 leading-relaxed">
      Different data, same goal — keeping AI agents accurate. <strong>context7</strong> retrieves documentation and code examples for programming libraries and frameworks (React, Django, Stripe SDK, etc.). <strong>openapi.city</strong> serves structured OpenAPI specifications — individual endpoints, auth details, request/response schemas. Use context7 when your agent needs to know <em>how to use a library</em>. Use openapi.city when it needs to know <em>how to call an API</em>.
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    <div class="collapse-title text-base font-semibold">How does it work with my AI agent?</div>
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      Your agent calls openapi.city via MCP or REST, gets back structured spec data, and uses it to write correct API integrations. No more guessing parameter names or reading 2.7MB spec files.
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    <div class="collapse-title text-base font-semibold">What's the difference between REST API and MCP?</div>
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      Same data, different protocol. Use the REST API for scripted pipelines and direct HTTP calls. Use the MCP server for agent-native tools — Claude, Cursor, Windsurf — where the agent discovers and calls tools automatically.
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    <div class="collapse-title text-base font-semibold">Which AI tools are supported?</div>
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      Anything that speaks MCP or HTTP. That includes Claude Code, Cursor, Windsurf, Copilot, OpenClaw, and custom agents. If it can call an API, it can use openapi.city.
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    <div class="collapse-title text-base font-semibold">How do schema references work?</div>
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      OpenAPI specs use <code class="text-primary/70 bg-primary/10 px-1 rounded text-xs">$ref</code> to reference other schemas. We keep responses lean by preserving refs — call <code class="text-primary/70 bg-primary/10 px-1 rounded text-xs">get_schemas</code> to fetch any nested schema on-demand. Smaller payloads, faster responses.
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    <div class="collapse-title text-base font-semibold">Can I add my own API specs?</div>
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      Yes — on the Pro plan. POST <code class="text-primary/70 bg-primary/10 px-1 rounded text-xs">/resolve</code> with a spec URL and we fetch, parse, and index it for your agents. <a href="/users/sign_up" class="text-primary font-semibold hover:underline">Upgrade to Pro &rarr;</a>
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    <div class="collapse-title text-base font-semibold">How are specs kept up to date?</div>
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      Weekly automated refreshes from source URLs. Swagger 2.0 specs are auto-converted to OpenAPI 3.0. Version history is tracked.
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    <div class="collapse-title text-base font-semibold">What happens if I exceed my monthly calls?</div>
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      Pro: €10 per 1,000 overage calls, billed automatically. Free: requests return 429 with a clear message. No surprise charges on either plan.
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    <div class="collapse-title text-base font-semibold">Do I need a credit card?</div>
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      No. The free tier (100 calls/month) starts immediately. Just tell your agent:
      <div class="mt-3 flex flex-col sm:inline-flex sm:flex-row sm:items-center gap-2 bg-base-100 border border-neutral rounded-lg px-4 py-3 max-w-full overflow-hidden">
        <code class="text-xs text-base-content/70 text-left break-all min-w-0">Sign up for openapi.city. Read https://openapi.city/signup.md for instructions.</code>
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