Steadfast

Browser agents that don't lose their sessions.

Steadfast is a Python library for running headless-browser automation across multiple accounts and platforms — with anti-detection, session persistence, and per-account isolation built in.

⚠️ Status: pre-alpha. APIs may shift before v0.1.0. Pin a commit if you depend on this in production today.

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Why Steadfast?

Every browser-agent platform — Stagehand, Browser Use, Skyvern, Anchor Browser, Hyperbrowser — has the same #1 customer complaint:

"My agent gets logged out every 4 hours."

That's a solved problem. Steadfast solves it like this:

Feature	Steadfast	Vanilla Playwright	Stagehand / Browser Use
Per-account fingerprint isolation	✅	❌	partial
Anti-detect init scripts built in	✅	❌	partial
Cookie import from browser extension	✅	manual	manual
Session capture via VNC (manual login)	✅	❌	❌
Session persistence across runs	✅	manual	partial
Sticky viewport + UA + proxy per account	✅	manual	❌
Old-reddit + new-reddit auto-fallback	✅	❌	❌

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Quickstart

pip install steadfast-browser    # dist name on PyPI
playwright install chromium

Note on the name: the package is installed as steadfast-browser on PyPI (the bare steadfast name was taken by an unrelated 2023 package), but it imports as steadfast — so pip install steadfast-browser, then from steadfast import ... in your code.

import asyncio
from pathlib import Path
from steadfast import AntiDetect, BrowserManager, BrowserManagerConfig
from steadfast.platforms import Twitter

async def main():
    bm = BrowserManager(
        BrowserManagerConfig(profiles_dir=Path("./profiles")),
        AntiDetect(),
    )
    await bm.start()

    twitter = Twitter(bm, account_key="my_twitter")
    await twitter.import_cookies(open("twitter_cookies.json").read())
    assert await twitter.ensure_logged_in()

    result = await twitter.post("Hello from Steadfast!")
    print(result.url)

    await bm.shutdown()

asyncio.run(main())

That's it. No login flow, no captcha solver, no session-expiry handling in your code. The cookies you imported keep working for weeks.

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What's in v0.1.0

Platforms

Platform	Auth	Post	Reply / Comment	Like / Upvote	Health check
Twitter / X	cookies / login	✅	✅	✅	✅
LinkedIn	cookies / login	✅	✅ (comment)	✅	✅
Reddit	cookies / login	✅	✅ (comment)	✅ (upvote)	✅

Core library

• BrowserManager — Playwright pool with per-account contexts, concurrency limits, lifecycle helpers.
• AntiDetect — sticky proxies, sticky user agents, sticky viewports, human-like delays + clicks + typing, plus anti-automation init scripts injected into every context.
• RemoteDisplay — optional virtual-display + VNC server for manual-login flows on headless servers.
• PostResult — slotted dataclass returned by every post/reply/comment.

Exception hierarchy

SteadfastError
├── BrowserError       # Playwright launch / context creation
├── ProxyError         # proxy pool issues
└── PlatformError      # base for platform-specific errors
    ├── LoginFailed
    ├── RateLimited
    └── AccountSuspended

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Examples

See examples/ for runnable scripts:

#	File	Demonstrates
1	01_twitter_post.py	Simplest possible post
2	02_linkedin_with_cookies.py	Cookie import + post (recommended auth pattern)
3	03_reddit_comment.py	old.reddit / new.reddit auto-fallback
4	04_session_save_restore.py	Sessions survive BrowserManager restart
5	05_multi_account.py	Two accounts running concurrently on one BM

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Documentation

• Getting started — install, first run, troubleshooting
• Auth & sessions — the wedge, explained
• Anti-detection — what's in the init script and why

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Why an open-core SaaS exists

The library above runs anywhere. But running it at scale — many tenants, each with many accounts, with observability, retries, scheduling, and session-rescue automation — is operational work most engineers don't want to write.

The hosted version of Steadfast does that part, billed monthly. More info at (coming soon).

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Project layout

steadfast/
  __init__.py              # public exports
  browser_manager.py       # Playwright pool
  anti_detect.py           # proxies, UAs, viewports, human-like helpers
  exceptions.py            # error hierarchy
  remote_display.py        # Xvfb + x11vnc for manual-login flows
  _log.py                  # KV-rendering logging adapter
  utils.py                 # small helpers (utcnow, async_retry, ...)
  platforms/
    twitter.py
    linkedin.py
    reddit.py
    _models.py             # PostResult dataclass
tests/                     # 85 tests, < 1s to run
examples/                  # 5 runnable scripts
docs/                      # mkdocs site

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Contributing

Bug reports + PRs welcome on GitHub. Before submitting:

pip install -e ".[dev]"
ruff check steadfast/ tests/
pytest -q

The full test suite runs in under one second and doesn't require launching a real browser — most of the real-browser code paths are tested via the examples on real platforms.

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License

Apache 2.0 with Commons Clause — see LICENSE.

You can use Steadfast for any commercial or non-commercial purpose, including paid client work. You can't host it as a competing SaaS product. If that's what you want, contact us at hello@steadfast.dev about a commercial license.