servo-fetch 0.12.0

Browser engine in a library — fetch, render, and extract web content.

servo-fetch

Python bindings for servo-fetch — fetch, render, and extract web content with an embedded Servo browser engine.

• No Chromium — single binary, no browser download
• JavaScript execution — full Servo engine with SpiderMonkey
• Schema extraction — declarative CSS-selector → structured JSON, no LLM
• Async-ready — asyncio.to_thread wrappers, AsyncClient with streaming crawl
• Typed — full .pyi stubs, works with ty / mypy / pyright

Install

pip install servo-fetch

Quick Start

import servo_fetch
page = servo_fetch.fetch("https://example.com")
page.html          # rendered HTML
page.inner_text    # document.body.innerText
page.markdown      # readable Markdown (lazy, cached)
page.title         # str | None

Schema Extraction

from servo_fetch import Schema, Field

schema = Schema(
    base_selector=".product",
    fields=[
        Field(name="title", selector="h2", type="text"),
        Field(name="price", selector=".price", type="text"),
        Field(name="url", selector="a", type="attribute", attribute="href"),
    ],
)

page = servo_fetch.fetch("https://shop.example.com", schema=schema)
page.extracted  # [{"title": "...", "price": "...", "url": "..."}]

Async

from servo_fetch import fetch_async, AsyncClient

page = await fetch_async("https://example.com")

async with AsyncClient(user_agent="MyBot/1.0") as client:
    async for page in client.crawl_stream("https://docs.example.com", max_pages=50):
        print(page.url, page.title)

Develop

Requires uv.

uv sync --group all              # create venv + install dev deps
uv run maturin develop           # build extension (debug, fast compile)
uv run pytest                    # run tests
uv run ruff check python tests   # lint
uv run ty check python           # type check

Troubleshooting

Linux: "cannot allocate memory in static TLS block"

Servo's native extension uses large thread-local storage. On some Linux systems, set before importing:

export GLIBC_TUNABLES=glibc.rtld.optional_static_tls=16384