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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.

Tests License Python PyPI

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 ✅ ❌ ❌

Quickstart

bash 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.

```python import asyncio import json 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() try: twitter = Twitter(bm, account_key="my_twitter") await twitter.import_cookies( json.loads(Path("twitter_cookies.json").read_text()) ) assert await twitter.ensure_logged_in() result = await twitter.post("Hello from Steadfast!") print(result.url) finally: 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.

What's in v0.1.0

Platforms

Platform Auth Post Comment Like Upload Health
Twitter / X cookies / login ✅ ✅ (reply) ✅ — ✅
LinkedIn cookies / login ✅ ✅ ✅ — ✅
Reddit cookies / login ✅ ✅ ✅ (upvote) — ✅
Facebook cookies / login ✅ ✅ ✅ — ✅
Instagram cookies / login ✅ (image) ✅ ✅ — ✅
YouTube cookies / login — ✅ ✅ ✅ (video) ✅

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

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

Examples

Runnable scripts live in the examples directory on GitHub:

# 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
6 06_facebook_post.py Facebook composer-dialog flow
7 07_youtube_comment.py YouTube comment with Google-domain + youtube-domain cookies
8 08_youtube_upload.py Video upload via YouTube Studio wizard
9 09_instagram_post.py Single-image post via Instagram web composer

Documentation

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).

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 facebook.py instagram.py youtube.py _models.py # PostResult dataclass tests/ # 130 unit tests + 3 real-browser integration tests examples/ # 9 runnable scripts docs/ # mkdocs site

Contributing

Bug reports + PRs welcome on GitHub. Before submitting:

bash pip install -e ".[dev]" ruff check steadfast/ tests/ mypy --strict steadfast/ pytest # 130 unit tests, ~1s pytest -m integration tests/integration # 3 real-browser tests, ~3s

The full unit suite runs in under one second and doesn't require launching a real browser — most real-browser code paths are exercised by the integration tests, which spin up a chromium context to verify the anti-detect init script actually applies in-browser.

License

Apache 2.0 with Commons Clause — see LICENSE on GitHub.

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 [email protected] about a commercial license.