# DaySurface HTTP API

> Every DaySurface tool is reachable over a plain HTTP API as well as over
> MCP and the CLI. One service registry backs all three, so behaviour is
> identical whichever you call.

- OpenAPI specification (machine-readable): https://daysurface.com/openapi.json
- Base URL: https://api.daysurface.com
- Rendered reference (browser): https://daysurface.com/api

The rendered reference draws itself in client-side JavaScript, so fetch
`https://daysurface.com/openapi.json` rather than scraping that page.

## Authentication

Send an `X-API-KEY` header, or an OAuth 2.1 bearer token audience-bound to the
MCP endpoint. Full recipe: https://daysurface.com/auth.md

## Prefer MCP for agents

If you are an agent, the MCP endpoint https://mcp.daysurface.com/mcp gives you the same
operations as typed, self-describing tools - discover them with `tools/list`
instead of reading the spec. Setup: https://daysurface.com/connect.md

## More

- Full description for LLMs: https://daysurface.com/llms-full.txt
- Human docs: https://daysurface.com/docs