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Capless documentation

Capless is analytics infrastructure for software that is written, run and queried by AI agents. It has two halves that share one data model:

• Web analytics + session replay: one script tag. 2.0 KB (brotli) for analytics; session replay is a separate 1.7 KB chunk loaded only for sampled sessions. No cookies.
• A headless data backend: three primitives behind one HTTP API at https://api.capless.sh/v1.
  1. Streams: durable, ordered, append-only collections of JSON records.
  2. Functions: deterministic, bounded CEL expressions for validation, filtering, mapping and erasure.
  3. Materializations: independently maintained copies of streams in ClickHouse, configured with real SQL.

Web analytics events land in a stream called web.events and replays in web.replay, so everything below applies to your web data too.

#Start here

• Quickstart: account, snippet, first query. Five minutes.
• For agents: the signup API, MCP and a curl-only flow an agent can run end to end.
• MCP server: connect Claude Code, Cursor or any MCP client.

#Reference

• Web SDK: snippet, JavaScript API, collected fields, replay privacy.
• Streams & cursors: batches, positions, durability, idempotency.
• Reading & change feed: /read, /changes, pagination and limits.
• Time seeking: jump to a commit time with /locate.
• CEL functions: variables, number and regex rules, examples.
• Erasures & GDPR: delete by predicate, everywhere.
• ClickHouse materializations: tables, sources, lineage, status.
• API reference: every endpoint group; full OpenAPI spec.
• Limits & quotas · Security & privacy

#Conventions

• Base URL https://api.capless.sh. All endpoints are under /v1.
• Authenticate with your project API key: authorization: Bearer cpl_….
• Bodies are JSON. Timestamps are UTC ISO 8601 with millisecond precision.
• IDs (str_, ent_, era_, mat_, src_) and cursors (cur_) are opaque strings.
• Errors are {"error": {"code", "message", "details"?, "requestId"}} with a stable code.
• Lists are paginated with limit + pageToken → {data, nextPageToken}.

Every page of these docs is also available as Markdown: append .md to its URL (this page: /docs/index.md). /llms.txt indexes them, and /llms-full.txt is everything in one file.