Summary
A hosted MCP endpoint that returns deterministic fake data so you can prototype agent workflows without spinning up a backend. You get 12 tools covering common patterns like list_users, get_product, create_order, send_email, and search_knowledge_base. All data is seeded from your inputs, so the same request returns the same mock response. Free tier gives you 30 requests per minute and 500 per day, rate limited by IP and user agent fingerprint. Supports streamable HTTP natively, which means it works in Claude Desktop, Cursor, and Claude Code without needing mcp-remote as a proxy. Built with the MCP SDK, Faker.js for seeded data generation, and Upstash Redis for sliding window rate limits.
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Hosted MCP endpoint returning realistic fake data for prototyping agents. Paste one URL, zero setup.
Live at mockmcp.io — https://mockmcp.io/mcp
Built for devs who want to prototype agent workflows without wiring up a backend, writing fixtures, or standing up a local MCP server. 12 pre-built tools covering the scenarios in most agent tutorials.
Try it
# Initialize a session and get back a session id
curl -i -X POST https://mockmcp.io/mcp \
-H "Content-Type: application/json" \
-H "Accept: application/json, text/event-stream" \
-d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"curl","version":"0.1"}}}'
# Use the Mcp-Session-Id header in subsequent calls:
curl -X POST https://mockmcp.io/mcp \
-H "Content-Type: application/json" \
-H "Accept: application/json, text/event-stream" \
-H "Mcp-Session-Id: <paste-id-here>" \
-d '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"list_users","arguments":{"limit":3}}}'
Connect your client
Claude Code
claude mcp add --transport http mockmcp https://mockmcp.io/mcp
Cursor — add to ~/.cursor/mcp.json:
{
"mcpServers": {
"mockmcp": {
"url": "https://mockmcp.io/mcp"
}
}
}
Claude Desktop — Settings → Connectors → Add custom connector → paste https://mockmcp.io/mcp as the URL.
No mcp-remote proxy required. All three clients speak Streamable HTTP natively.
Tools
| Tool | What it does |
|---|---|
list_users | Paginated list of mock users |
get_user | One mock user by id or seed |
create_user | Create a mock user (no persistence) |
list_products | Paginated list of mock products |
get_product | One mock product |
list_orders | Mock orders with optional status filter |
get_order | One mock order |
create_order | Create a mock order (no persistence) |
list_events | Mock analytics events |
create_event | Record a mock event |
send_email | Returns fake success, nothing delivered |
search_knowledge_base | Mock KB search with ranked results |
All data is seeded from your inputs — same input, same output.
Limits
Free tier, per hashed IP + User-Agent fingerprint:
- 30 requests per minute
- 500 requests per day
Hit the wall? Drop your email at mockmcp.io/waitlist for paid-tier access when it launches.
429 responses carry a structured JSON-RPC error with upgrade_url and retry_after_seconds. Every successful response carries X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, and X-RateLimit-Scope headers.
Run locally
npm install
npm run dev
Server listens on http://localhost:3000. MCP endpoint at /mcp. Without Upstash env vars, rate limiting falls back to an in-memory store (per-process, fine for dev).
Stack
@modelcontextprotocol/sdk— MCP server + Streamable HTTP transport- Raw Node
http— no framework overhead, clean shutdown @faker-js/faker— deterministic fake data via seeds@upstash/ratelimit+@upstash/redis— sliding-window rate limitingzod— tool input validation
Deploy (for forks)
Targets Node 20+. Build + start are pinned via nixpacks.toml; health checks + restart policy via railway.json.
- Fork this repo, push to GitHub.
- Railway → New Project → Deploy from GitHub → pick your fork.
- Add env vars in Railway → Variables:
| Var | Notes |
|---|---|
UPSTASH_REDIS_REST_URL | From upstash.com free tier |
UPSTASH_REDIS_REST_TOKEN | Paired with the URL above |
PORT | Railway sets this automatically |
- Railway service → Settings → Networking → Custom Domain → paste your domain → follow the DNS instructions.
Health check
GET /health returns {"ok":true}. Railway pings this during deploy.
Waitlist signups
POST /api/waitlist logs a structured JSON line per signup:
{"event":"waitlist_signup","email":"alice@example.com","at":"2026-04-24T19:33:06.396Z"}
Grep them with railway logs | grep waitlist_signup. Storage-free by design — swap in Resend, a Tally forward, or a DB when the paid tier is live.
License
MIT — see LICENSE.
Featured
Fastest browser for AI agents to run web automation tasks, always free.
Download Free life-time →Notes, actions and memory. Without a meeting bot. First month 100% off.
Download for free →belt cli automatically finds the best tools and skills for your agent. image, video, music, tts...
one prompt install →Connect your Claude agent to live crypto prices and trading routes via 1inch
Get the MCP →Block distracting apps from your iPhone permanently without a 3rd party app. Free and open source.
Block now (100% free) →
