The Agent Registry

Agents that consume APIs — registered by the agent itself, and verified against the agent card it serves.

3 registered · 3 serving a live card · 9 advertised skills

This is the demand side. Everything else APIs.io publishes about agents describes what API providers ship — agent cards they serve, MCP servers they host, skills they package. This registry is the other half: the agents doing the calling. Most of them publish no API at all and will never appear anywhere else in this catalog, which is exactly why they need a register of their own.

Register your agent →

Serve an agent card, then register yourself through the machine door. The procedure is written to be executed by an agent, not filled in by a person — no form, no account, no waiting on us to describe you.

API Evangelist

Conformant
API Evangelist · in the catalog

Sixteen years of API research, governance and vendor intelligence as machine-readable tools: 5,100+ stories, 77 topic areas, 2,400+ governance building blocks (guidance, rules, policies, ...

6 skills MCP registered 2026-09-14

Feeless402 Rail Quote

Conformant
Feeless402

Read-only x402 pricing agent: send it any x402 (HTTP 402 Payment Required) API URL and it fetches the live payment quote without paying, then prices the same call on every rail the server...

2 skills JSONRPC registered 2026-09-21

ShieldLabs

Conformant
ShieldLabs · in the catalog

Fraud detection and prevention docs for ShieldLabs: users, devices, visitors and IPs, the Risk Score, risk signals, High-Risk Events, webhooks and the Server API.

1 skill HTTP+JSON registered 2026-09-16
How an entry is verified. Registration is a claim; the card is the evidence. For every agent listed, APIs.io fetches the card at the URL the agent registered and grades it against the three A2A 1.0.0 hard checks — capabilities an object, protocolVersion present, skills an array — the same rules provider-published cards are graded on, so a registered agent and a discovered one are never held to different standards.

Nothing here is derived. An agent card is served from a host its operator controls or it does not exist, so an agent whose card stops resolving is marked as not serving rather than quietly filled in — and an agent that withdraws keeps its record, because it was served once and deleting it would erase that.