# aptu.dev

> Machine-payable API infrastructure for autonomous agents. Instant per-call settlement via x402 using USDC on Base and Solana. No account, no API key, no signup.

Four paid endpoints are live: POST /v1/echo settles $0.01 USDC on Base or Solana via x402, POST /v1/resume-eval settles $0.005 USDC on Base or Solana via x402, POST /v1/agent-readiness settles $0.05 USDC on Base or Solana via x402, and GET /v1/btc-regime settles $0.003 USDC on Base or Solana via x402.

## Docs

- [Homepage](https://aptu.dev/): one-pager describing aptu.dev
- [llms-full.txt](https://aptu.dev/llms-full.txt): full-content companion to this file
- [skill.md](https://aptu.dev/skill.md): agent skill description with frontmatter
- [rss.xml](https://aptu.dev/rss.xml): RSS 2.0 changelog feed of paid endpoint and price changes
- [OpenAPI](https://aptu.dev/v1/openapi.json): OpenAPI 3.1 document for free GET surfaces
- [api-catalog](https://aptu.dev/.well-known/api-catalog): RFC 9727 linkset document
- [auth.md](https://aptu.dev/auth.md): agent registration declaration (anonymous access)
- [agents.txt](https://aptu.dev/agents.txt): agent notes for this site
- [agent-skills index](https://aptu.dev/.well-known/agent-skills/index.json): agentskills.io discovery index
- [MCP server card](https://aptu.dev/.well-known/mcp.json): MCP server card describing the /mcp transport and paid tools

## Agent Discovery

- [ard.json](https://aptu.dev/.well-known/ard.json): ARD v0.91 manifest declaring every agent-readable surface on aptu.dev
- [webmcp.json](https://aptu.dev/.well-known/webmcp.json): WebMCP tool manifest describing the browser-side document.modelContext tools
- [agent-card.json](https://aptu.dev/.well-known/agent-card.json): A2A v1.0 agent card; transport POST /a2a (JSONRPC)
- [http-message-signatures-directory](https://aptu.dev/.well-known/http-message-signatures-directory): RFC 9421 Web Bot Auth key directory (draft-ietf-webbotauth-httpsig-protocol)
- [web-bot-auth.json](https://aptu.dev/.well-known/web-bot-auth.json): Ed25519 public JWK signing aptu.dev's outbound probe requests

## Endpoints

- [/.well-known/x402](https://aptu.dev/.well-known/x402): x402 discovery manifest
- [/.well-known/mcp.json](https://aptu.dev/.well-known/mcp.json): MCP server card
- [/mcp](https://aptu.dev/mcp): MCP Streamable HTTP transport (tools: echo_probe, resume_eval, agent_readiness, btc_regime)
- [/a2a](https://aptu.dev/a2a): A2A JSON-RPC transport (method SendMessage; text `search: <query>`)
- [/v1/catalog](https://aptu.dev/v1/catalog): JSON endpoint catalog
- [/v1/x401-probe](https://aptu.dev/v1/x401-probe): free x401 draft-0.2.0 demand probe (401 + PROOF-REQUEST)
- [/v1/echo](https://aptu.dev/v1/echo): paid echo probe, $0.01 USDC on Base or Solana via x402
- [/v1/resume-eval](https://aptu.dev/v1/resume-eval): paid resume ATS rubric scorer, $0.005 USDC on Base or Solana via x402
- [/v1/agent-readiness](https://aptu.dev/v1/agent-readiness): paid domain agent-readiness auditor (score 0-100 + findings), $0.05 USDC on Base or Solana via x402
- [/v1/btc-regime](https://aptu.dev/v1/btc-regime): paid BTC spot vs 7-day MA regime gate (query params), $0.003 USDC on Base or Solana via x402
- [/v1/self-check](https://aptu.dev/v1/self-check): free deterministic scorer self-check with SHA-256 fixture hashes
- [/v1/openapi.json](https://aptu.dev/v1/openapi.json): OpenAPI 3.1 document
- [/terms.txt](https://aptu.dev/terms.txt): service terms (experimental, non-custodial, 424 failures do not settle)
- [/llms.txt](https://aptu.dev/llms.txt): this file
- [/llms-full.txt](https://aptu.dev/llms-full.txt): full content for machine readers
- [/rss.xml](https://aptu.dev/rss.xml): RSS 2.0 changelog feed of paid endpoint and price changes

## Usage

Fetch the discovery manifest:

```sh
curl -s https://aptu.dev/.well-known/x402
```

Negotiate a JSON root document:

```sh
curl -s -H "Accept: application/json" https://aptu.dev/
```

## Notes

GET /v1/catalog is free. POST /v1/echo, POST /v1/resume-eval, POST /v1/agent-readiness, and GET /v1/btc-regime are paid; their payment requirements use the x402 protocol with an HTTP 402 challenge returned as a Base64-encoded PAYMENT-REQUIRED header. For the full handshake recipe, payer prerequisites, a paid-client snippet, and exact per-endpoint response keys, see How to pay in https://aptu.dev/skill.md and https://aptu.dev/llms-full.txt.