HTTP API · operational

Postman Echo

Postman's hosted request echo service: GET/POST echo, status codes, auth flows, cookies and delays, no key required.

Postman Echo mirrors back whatever an agent sends, which makes it a second, independent way to validate an HTTP client when httpbin is rate limited or down. Covers /get, /post, /put, /patch, /delete, /status/{code}, /delay/{n}, /basic-auth, /digest-auth, /time/* helpers and cookie endpoints. Maintained by Postman, no account needed.

endpoint: https://postman-echo.com/get
auth: none
try it: tested example call
curl -s https://postman-echo.com/get?agent=nexus
capabilities: echo an http request · return an arbitrary status code · simulate a slow response · test basic auth · test cookies
tags: test · testing · http · echo · debug · devtools
pricing: Free, no account.
i/o: HTTP GET/POST/PUT/PATCH/DELETE with any headers or JSON body → JSON
docs: https://learning.postman.com/docs/developer/echo-api/
machine-readable: /api/public/registry/postman-echo-api

Follow this tool

Get an alert when Postman Echo goes down, comes back, or quietly changes shape (response schema or tool list). Free for up to 3 tools. Pro: 100 tools + webhooks for your agents.

Get a key in one call

No account, no card

100 calls/day anonymous · 1,000/day with this free key · 50,000/day on Agent Pro. The key is returned instantly in the response — send it as the x-api-key header on any /api/public/* request. The key also lets you follow up to 3 tools and get an alert when one goes down or quietly changes shape. Email is optional; add yours to receive alerts, then confirm them from your inbox.

tested example call

curl -s -X POST https://agentnexus.app/api/public/keys \
  -H 'content-type: application/json' \
  -d '{"agent":"my-agent","purpose":"tool discovery","email":"you@example.com"}'

Use it from your agent

Point any MCP-capable agent (Claude, Cursor, your own) at the no-auth endpoint — it can then find Postman Echo and every other listed interface on its own:

tested example call

claude mcp add --transport http agent-nexus https://agentnexus.app/api/public/mcp

Agents can discover Postman Echo through the Agent Nexus MCP server, /llms.txt or the discovery API.