serving-the-api

Serving the API

crawlberg serve starts a long-running REST API server exposing the crawl engine over HTTP. The endpoints are Firecrawl v1-compatible, so existing Firecrawl clients and SDKs can point at a local crawlberg instance.

This subcommand requires the binary to be built with the optional api feature (non-default). The Homebrew tap is built with all features, so serve is available there; a from-source build needs cargo install crawlberg-cli --features api (or --features all) to include it.

Quick recipe

crawlberg serve --host 127.0.0.1 --port 3000

It logs Starting REST API server on <host>:<port> to stderr and blocks until terminated. Hit GET /health to confirm it is up.

Flags

Flag	Default	Purpose
--host	0.0.0.0	Address to bind to.
--port	3000	Port to listen on.

serve does not take the per-request crawl flags — it boots with the default CrawlConfig and accepts per-request options in each HTTP request body.

Endpoints

Firecrawl v1 surface:

Method + path	Purpose
POST /v1/scrape	Scrape a single URL (synchronous).
POST /v1/crawl	Start an asynchronous crawl job → returns a job id.
GET /v1/crawl/{id}	Poll crawl job status and collect results.
DELETE /v1/crawl/{id}	Cancel a running crawl job.
POST /v1/map	Discover URLs on a site (synchronous).
POST /v1/batch/scrape	Start an asynchronous batch-scrape job → job id.
GET /v1/batch/scrape/{id}	Poll batch-scrape job status and results.
POST /v1/download	Download a document from a URL.

Operational:

Method + path	Purpose
GET /health	Health check ({ status, version }).
GET /version	Version information.
GET /openapi.json	OpenAPI schema for the whole surface.

Request bodies use camelCase fields. Scrape/crawl/map mirror the CLI: url, formats, onlyMainContent, includeTags/excludeTags, timeout for scrape; url, maxDepth, maxPages, includePaths/excludePaths for crawl; url, limit, search for map. Responses wrap data as { success, data | error }; async jobs return { success, id } and are polled for { status, total, completed, data, error }.

Examples

Scrape via HTTP

curl -s http://127.0.0.1:3000/v1/scrape \
  -H 'content-type: application/json' \
  -d '{"url":"https://example.com","formats":["markdown"]}' | jq '.data'

Start a crawl job and poll it

id=$(curl -s http://127.0.0.1:3000/v1/crawl \
  -H 'content-type: application/json' \
  -d '{"url":"https://example.com","maxDepth":2,"maxPages":100}' | jq -r '.id')

curl -s "http://127.0.0.1:3000/v1/crawl/$id" | jq '{status,completed,total}'

Map URLs

curl -s http://127.0.0.1:3000/v1/map \
  -H 'content-type: application/json' \
  -d '{"url":"https://example.com","limit":500,"search":"docs"}' | jq '.data'

Operational notes

• The server accepts CORS from any origin and ships no built-in authentication — do not expose it on a public interface. Bind to 127.0.0.1 for local use, or put it behind a reverse proxy / gateway that enforces auth and rate limiting before exposing it more widely.
• Request bodies are capped at 10 MB and each request times out after 5 minutes.
• Crawl and batch-scrape are asynchronous: the POST returns a job id immediately and you poll the {id} endpoint until status is completed, failed, or cancelled.

When to run serve vs. CLI vs. MCP

• CLI (scrape/crawl/map/interact) — one-shot jobs, shell pipelines, scripting. No long-running process.
• MCP (crawlberg mcp) — driving the crawler from an AI agent harness (Claude Code, Codex, Cursor, Gemini, opencode). Auto-registered by this plugin; prefer it inside an agent.
• serve (crawlberg serve) — a persistent HTTP service for other applications or non-agent clients that speak REST, or when you want Firecrawl-v1 compatibility. Choose it when many callers need the crawler over the network rather than one agent or one shell.