kreuzberg-dev 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
127.0.0.1for 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
idimmediately and you poll the{id}endpoint untilstatusiscompleted,failed, orcancelled.
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.