Capabilities

GET /v1/capabilities returns a JSON snapshot of what the running instance supports. Clients and agents can call it on startup to adapt their behavior — instead of guessing what a self-hosted deployment has configured, ask.

Request

GET https://api.fastcrw.com/v1/capabilities
Authorization: Bearer YOUR_API_KEY

No request body. No query parameters.

Response Shape

{
  "version": "0.23.0",
  "llm": {
    "providers": ["anthropic", "openai", "deepseek", "openai-compatible", "openai-responses", "azure"],
    "supportsBaseUrl": true,
    "serverKeyConfigured": false,
    "maxConcurrency": 0
  },
  "formats": {
    "supported": [
      "markdown", "html", "rawHtml", "plainText",
      "links", "json", "summary", "changeTracking", "screenshot"
    ],
    "llmRequired": ["json", "summary"],
    "changeTrackingModes": ["gitDiff", "json"],
    "changeTrackingModesLlmRequired": ["json"]
  },
  "search": {
    "supported": true,
    "answer": false,
    "summarizeResults": false
  },
  "screenshot": {
    "supported": true,
    "fullPage": true
  },
  "renderers": {
    "available": ["lightpanda", "chrome"],
    "mode": "auto"
  },
  "extract": {
    "supported": true,
    "maxUrls": 50,
    "perFieldAttribution": true
  },
  "documents": {
    "parsers": ["pdf"],
    "fileUpload": {
      "supported": true,
      "endpoint": "/firecrawl/v2/parse",
      "maxBytes": 52428800,
      "types": ["application/pdf"],
      "ocr": false
    }
  },
  "limits": {
    "maxBatchUrls": 10000,
    "maxExtractUrls": 50,
    "searchDefaultLimit": 5,
    "searchMaxLimit": 20,
    "maxUploadBytes": 52428800
  }
}

All keys use camelCase.

The Contract

Every boolean in this response is derived from the real build (compiled cargo features) and the effective config. Nothing is hardcoded to true.

A capability reads true only when the instance can perform the operation for a well-formed request that supplies no extra credentials. Credentials are reported separately rather than folded into the booleans:

• llm.serverKeyConfigured tells you whether a server-side LLM key exists.
• formats.llmRequired tells you which formats need an LLM at all.

Bring-your-own-key is always accepted and cannot be turned off. So on a BYOK-only deployment you will see search.supported: true alongside search.answer: false: the instance cannot answer on its own, but a request that carries llmApiKey still gets an answer. Gate on search.supported if you supply your own key; gate on search.answer if you do not.

Fields

version

string — The server binary's semver version (CARGO_PKG_VERSION).

llm

formats

search

screenshot

renderers

extract

documents

limits

Only enforced caps appear here. Each value is the one the server actually applies, not a documented default.

Reading a Deployment

The two deployment shapes differ in exactly one interesting way — where the LLM key lives.

BYOK-fronted (a SaaS or gateway in front of the engine). The gateway injects an LLM key on each request, so the engine itself has none: llm.serverKeyConfigured is false, and therefore search.answer and search.summarizeResults are false too. search.supported is still true. This is not a missing feature — it is the honest statement that the engine alone, with no caller-supplied key, cannot answer. Callers that send llmApiKey get answers.

Self-hosted with a server key. [extraction.llm] api_key is set, so llm.serverKeyConfigured is true and search.answer follows search.supported.

Everything else (renderer tiers, screenshot capture, parsers, limits) varies per deployment and cannot be predicted without asking.

Using Capabilities at Runtime

Agents and SDKs

Call GET /v1/capabilities once on startup and cache the result. Use it to:

• decide whether to send formats: ["json"] (check formats.supported contains "json")
• decide whether to supply llmApiKey in the body (check llm.serverKeyConfigured, and formats.llmRequired for which formats need one)
• decide whether to offer screenshots (check screenshot.supported — never assume it from the presence of a renderer)
• decide whether to offer file-upload UI or API paths (check documents.fileUpload.supported, and size the client-side guard from limits.maxUploadBytes)
• confirm whether changeTracking is available before using monitor scrapes (check formats.supported contains "changeTracking")
• size batch requests against limits.maxBatchUrls instead of discovering the cap through a rejection

import httpx

caps = httpx.get(
    "https://api.fastcrw.com/v1/capabilities",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
).json()

if caps["llm"]["serverKeyConfigured"]:
    llm_key_in_body = None          # server has a key
else:
    llm_key_in_body = "sk-..."      # caller must supply a per-request key

pdf_ok = caps["documents"]["fileUpload"]["supported"]
can_screenshot = caps["screenshot"]["supported"]

# Gate on `supported` when you bring your own key; on `answer` when you do not.
if llm_key_in_body:
    can_answer = caps["search"]["supported"]
else:
    can_answer = caps["search"]["answer"]

Self-Hosted Instances

Self-hosted deployments differ from the hosted API in several ways a caller cannot predict without checking:

• PDF parsing may be disabled ([document] enabled = false) or not compiled in
• A server-side LLM key may or may not be configured
• The [document] max_upload_bytes limit can be set below 50 MiB
• The search backend may not be connected ([search] searxng_url unset)

Always call /v1/capabilities before making assumptions about what a self-hosted instance can do.

Authentication

GET /v1/capabilities is an authenticated route on both hosted and self-hosted deployments (when API keys are configured). The response contains no secrets, but it describes deployment configuration, which is worth protecting.

On a self-hosted instance with no API keys configured, the route is public.

What To Read Next

• Output Formats — the 9 formats and when to use each
• PDF Parsing — the POST /firecrawl/v2/parse upload endpoint
• Search — POST /v1/search and the LLM answer path
• Self-Hosting — configuration reference for [document], [extraction.llm], and [search]