Oxylabs Web API — MCP Server

mcp-name: io.oxylabs/web-api-mcp

Welcome to the official repository overview for Oxylabs' Web API MCP. This guide is a developer-focused, technical reference covering Web API MCP. A self-hostable Model Context Protocol server that gives any MCP-capable agent live web access through the Oxylabs Web API.

| Tool | What it does | |---|---| | search | Search the live web, returns ranked organic results (title, description, URL) | | scrape | Read a single URL as Markdown by default, including JS-heavy and bot-protected pages. Ask for a screenshot, or pass json_prompt / json_schema to pull named fields off it as JSON | | check_scrape | Collect the result of a scrape the API is running in the background | | read_scraped | Read a large page that was offloaded to disk, in chunks | | list_scrapers | List the scrape endpoints the API implements, grouped by parser support, or describe one's parameters | | scrape_target | Call a target-specific scrape endpoint with its own parameters, as content or as structured JSON |

All six are annotated readOnlyHint — nothing here writes anything — so clients can run them without prompting.

The skill ships with the server

Connecting the server is the whole install. The agent skill is bundled in the package and served as an MCP resource and a prompt, so a client that never adds the web-api-skills repo still gets the judgment for using these tools well — search to find and scrape to read, when JavaScript rendering earns its cost, what to do with an empty page, how to cite.

| | | |---|---| | oxylabs://skill/web-api | The skill itself, as Markdown | | prompt web_research | Takes a question, hands the agent the task plus the skill |

scripts/sync-skill.sh refreshes the bundled copy from the skills repo — the canonical copy lives there, and the two must not drift.

Fitting the client's context

Oversized content is measured in tokens, not characters: 40 000 characters of English is about 10 000 tokens, but 40 000 characters of Chinese is about 40 000, and Claude Code, Claude Desktop and Cursor all reject a tool result over 25 000. The estimate is script-aware for that reason. The budget is OXYLABS_MAX_INLINE_TOKENS (default 10 000), and a client that knows its own limit can override it per request with an X-MCP-Max-Tokens header — 0 opts out entirely.

Sync first, queued only on a timeout

Every scrape goes to the synchronous endpoint first. If it times out, the same request is sent to the corresponding asynchronous endpoint (/v1/async/...) and the agent gets a request id to poll. async/... endpoints passed to scrape_target are always queued.

{ "state": "pending", "request_id": "7504857924934611969", "note": "The synchronous call timed out (…), so the same request was queued instead. … call check_scrape('7504857924934611969') …" }

The agent polls check_scrape(request_id) every 5s while it is pending. The API holds the result, so nothing about a request lives in this process: restarts and extra replicas do not lose it.

It says when a page needed rendering

The agent shouldn't have to guess whether an empty page is empty or just unrendered, and it shouldn't pay for a render on every page to find out. So a plain scrape that comes back with almost no visible text — or with a "please enable JavaScript" notice — is flagged:

{
  "content": "# Loading…",
  "content_thin": {
    "visible_chars": 9,
    "reason": "almost no text",
    "note": "…renders client-side. Retry the same call with run_js=True…"
  }
}

HTML is measured on its text, not its markup, so a 3 KB shell of <meta> tags still reads as thin. The flag is a hint, not a retry: rendering is slow and billed, and a genuinely short page would pay for it on every fetch. The threshold is 500 visible characters.

Structured data

Request structured data and the server selects the parser for you:

• Dedicated parser — included at no extra cost. Available on selected target endpoints, it returns that endpoint's predefined structure.
• AI parser — billed on top of the scrape. Available on most endpoints, it returns exactly the fields your prompt or schema describes.

To keep costs down, the server tries the dedicated parser first and falls back to the AI parser only when the endpoint has no dedicated parser or the dedicated parse fails. Each result states which parser produced it, and the agent can request the AI parser directly when a dedicated result lacks the fields it needs.

Large pages

Web pages routinely exceed what is sensible to hand an agent in one response, so scrape does not return oversized content inline:

• Running locally (stdio): the page is written to a temp file. The agent gets the first 2 000 characters plus a path, and pulls the rest through read_scraped(path, offset) — reading only as far as it needs instead of paying for the whole page up front.
• Running remotely (HTTP): there is no shared filesystem, so a path would be useless. The content is truncated with a note stating the full length.

The threshold is OXYLABS_MAX_INLINE_TOKENS (default 10 000). read_scraped can only read files in the spill directory — it is deliberately not a general file reader.

Full API documentation: Oxylabs Web API docs

Requirements

• Python 3.10+ (built on FastMCP, installed with the package)
• An Oxylabs Web API key — in the Oxylabs dashboard, create a Web API instance and generate a key for it

Install

uv tool install git+https://github.com/oxylabs/web-api-mcp

That puts oxylabs-web-api-mcp on your PATH in its own environment. pipx install git+https://github.com/oxylabs/web-api-mcp does the same. Installing into a system Python usually fails — most are marked externally managed and refuse. To work on the server itself:

git clone https://github.com/oxylabs/web-api-mcp.git
cd web-api-mcp
pip install -e .

server.json is the MCP registry manifest. It has no packages block yet — add one once the server is published somewhere installable, since a registry entry pointing at nothing is worse than no entry.

Use it locally (stdio)

Point your client at the installed command. Claude Code:

claude mcp add oxylabs-web-api \
  --env OXYLABS_WEB_API_KEY=your_api_key_here \
  -- oxylabs-web-api-mcp

Claude Desktop / Cursor / any client that reads a JSON config:

{
  "mcpServers": {
    "oxylabs-web-api": {
      "command": "oxylabs-web-api-mcp",
      "env": { "OXYLABS_WEB_API_KEY": "your_api_key_here" }
    }
  }
}

Self-host it (HTTP)

The HTTP transport is for running one shared server for a team or for agents that can't spawn local processes.

export OXYLABS_WEB_API_KEY=your_api_key_here
export MCP_ALLOWED_HOSTS='mcp.internal.example.com,localhost:*'
oxylabs-web-api-mcp --transport http --host 0.0.0.0 --port 8080

The endpoint is then http://<host>:8080/mcp.

Docker

docker build -t oxylabs-web-api-mcp .
docker run --rm -p 8080:8080 \
  -e OXYLABS_WEB_API_KEY=your_api_key_here \
  -e MCP_ALLOWED_HOSTS='localhost:*,mcp.internal.example.com' \
  oxylabs-web-api-mcp

MCP_ALLOWED_HOSTS is not optional. The HTTP transport turns on DNS-rebinding protection, so a server that doesn't declare its own hostname rejects every request with a Host header it doesn't recognise (421 Misdirected Request). List the hostname clients actually connect to. host:* matches any port on that host.

Configuration

| Variable | Default | Purpose | |---|---|---| | OXYLABS_WEB_API_KEY | (required on stdio) | Web API key, sent as Authorization: Bearer <key>. Over HTTP a per-request Authorization: Bearer header takes precedence | | OXYLABS_BASE_URL | https://webapi.oxylabs.io | Override the API base URL, e.g. to go through a proxy | | OXYLABS_RETRIES | 2 | Retries on a transient 429/500/502/503/504 | | OXYLABS_RATE_LIMIT | (off) | Cap this server's own spend, e.g. 100/1h, 50/30m | | OXYLABS_MAX_INLINE_TOKENS | 10000 | Above this, content is offloaded or truncated | | OXYLABS_SPILL_DIR | system temp | Where offloaded pages are written (stdio only) | | OXYLABS_SPILL | 1 | Set to 0 to keep everything inline even on stdio | | MCP_TRANSPORT | stdio | stdio or http | | HOST / PORT | 127.0.0.1 / 8080 | HTTP transport bind address | | MCP_ALLOWED_HOSTS | localhost:*,127.0.0.1:* | Comma-separated Host allowlist (HTTP only) | | MCP_ALLOWED_ORIGINS | (empty) | Comma-separated Origin allowlist (browser clients) |

Copy .env.example to .env for local use. On stdio the server reads that .env from its working directory: any OXYLABS_* name not already set in the environment is filled from there, so a project that keeps its key in .env needs no launcher wrapper. Real environment variables always win, and only OXYLABS_* names are read. Point it elsewhere with OXYLABS_ENV_FILE=/path/to/.env.

The key is read at request time and is never written to disk or logged.

Security notes

• Callers can bring their own key over HTTP. Send Authorization: Bearer <key> with each request and the server uses it for that call, so one deployment serves several callers on their own quota. OXYLABS_WEB_API_KEY in the server environment is the fallback when no header arrives.
• Cap the spend. OXYLABS_RATE_LIMIT=100/1h refuses tool calls past a sliding window, so a runaway agent loop cannot drain the key. Off by default.
• If you rely on that fallback, treat the endpoint as privileged. The server does no authentication of its own — anyone who can reach it spends the key it holds. Put it behind your VPN, an ingress with auth, or a service mesh. Don't expose it to the public internet.
• scrape fetches whatever URL it is given. If you expose this server to untrusted prompts, restrict egress at the network layer rather than trusting the caller.
• read_scraped is restricted to the spill directory. Don't point OXYLABS_SPILL_DIR at a directory holding anything else — it would make those files readable by the agent.

Development

pip install -e '.[dev]'
ruff check . && ruff format --check .
pytest                         # or: python tests/test_server.py
./scripts/sync-skill.sh        # refresh the bundled skill from web-api-skills

The tests are offline: error parsing, input validation, envelope trimming, endpoint-name handling, sync-first scraping with the queued fallback and polling, and the dedicated/AI parser selection. CI runs the same on 3.10, 3.12 and 3.13.

Learn More

For detailed configuration, advanced usage, and code examples in multiple languages, check the official documentation:

• Get started with Web API
• Web API documentation

License

MIT

Contact Us

If you have questions or need support, reach out to us at support@oxylabs.io, or through live chat in the Oxylabs Dashboard. For enterprise inquiries, contact your dedicated account manager.