Stealth browser REST API — drive a bot-proof browser with curl

Sallyport wraps Fortress — a stealth Chromium engine with C++-level fingerprint spoofing — behind a REST API. Any agent, script, or human can browse the web through a bot-proof browser with simple HTTP calls.

No Playwright scripts. No CDP boilerplate. No anti-bot configuration.

A sallyport is a controlled passage through a fortress wall — the secure way in and out.

Why?

• Bypasses anti-bot — Fortress corrects canvas, WebGL, audio, fonts, navigator, and 30+ fingerprint surfaces inside Chromium's C++. CreepJS: 0%. Live Cloudflare Turnstile: cleared. Akamai Bot Manager: bypassed.
• Agent-friendly — REST API instead of Playwright. Any agent that speaks HTTP can browse.
• Camofox-compatible — Same endpoint pattern (POST /tabs, GET /tabs/{id}/snapshot).
• Open source — MIT license. Build on it, fork it, ship it.

Known limits

Sallyport inherits some constraints from the upstream Fortress engine and its own architecture. These are surfaced here so you can decide when it's the right tool.

Limit	Detail	Workaround
Cloudflare Turnstile Managed Challenge	Fortress cannot bypass interactive Turnstile captchas (the checkbox/puzzle-wall variant). The snapshot returns a Cloudflare challenge page, not real content.	Use a residential proxy or try the URL via Wayback Machine / Google cache. This is a Fortress engine limitation.
Datacenter IP blocking	Servers that block datacenter IP ranges will reject requests regardless of browser fingerprint.	Use a residential proxy via the engine's proxy config (planned).
Single browser instance	Only one Fortress instance at a time. Switching personas requires stop/start.	N/A — architectural limit tracked for v0.2.0.
No crash recovery	If Fortress crashes mid-session, the engine enters a broken state. Manual stop/start required.	Tracked for v0.2.0.
No concurrent request locks	Shared mutable state (tabs, browser ref) has no threading locks. Unlikely to race on single-user setups.	Tracked for v0.2.0.
No cookie/session persistence	Each tab opens a fresh context. Auth sessions are lost on tab close.	Tracked for v0.2.0.

Full issue tracker →

Benchmarks

Measured on a Mac Mini (Apple M-series, ARM64) with Sallyport v0.1.0 + Fortress stable:

Operation	Median	Worst case
Open tab	1.43s	3.07s
Snapshot (simple page)	5.2ms	43.6ms
Snapshot (heavy page)	65.6ms	187.8ms
JS evaluate	3.8ms	51.4ms
Scroll	14.7ms	22.0ms
Screenshot	47.9ms	97.7ms

Full benchmark methodology and raw data →

Quick start

Docker

docker run -d --rm --platform linux/amd64 --shm-size=1g -p 9378:9378 fromthescope/sallyport:latest

Local

pip install sallyport
python3 -m sallyport.server

Then:

# Start the stealth browser engine
curl -X POST http://localhost:9378/browser/start \
  -H "Content-Type: application/json" \
  -d '{"channel":"stable"}'

# Open a page — even Cloudflare/Akamai protected ones
curl -s -X POST http://localhost:9378/tabs \
  -H "Content-Type: application/json" \
  -d '{"url":"https://bot.sannysoft.com","wait_ms":4000}' \
  | python3 -c "import json,sys; d=json.load(sys.stdin); print(d['snapshot'][:500])"

# Close up
curl -X DELETE "http://localhost:9378/tabs/<tab_id>"
curl -X POST http://localhost:9378/browser/stop

API

Method	Endpoint	Description
GET	/health	Server status, tab count, uptime
GET	/config	Server config and feature flag state
POST	/browser/start	Launch Fortress with optional persona
POST	/browser/stop	Kill Fortress, clean up all tabs
POST	/tabs	Open URL → tab ID + snapshot
GET	/tabs/{id}/snapshot	Accessibility tree content
GET	/tabs	List all open tabs with URL, age
GET	/tabs/{id}/source	Raw rendered HTML (full DOM after JS)
POST	/tabs/{id}/scroll	Scroll up/down/left/right by px
POST	/tabs/{id}/screenshot	Base64 PNG screenshot (supports full_page)
POST	/tabs/{id}/click	Click element by ref
POST	/tabs/{id}/type	Type text into element
POST	/tabs/{id}/evaluate	Run JS, get result
POST	/tabs/{id}/navigate	Navigate existing tab
DELETE	/tabs/{id}	Close tab

Example: persona override

# Start with a specific browser persona
curl -X POST http://localhost:9378/browser/start \
  -H "Content-Type: application/json" \
  -d '{
    "channel":"stable",
    "persona": {
      "timezone":"America/New_York",
      "languages":"en-US,en",
      "hw_concurrency":16,
      "screen_width":1920,
      "screen_height":1080
    }
  }'

Architecture

Agent/Hermes ──curl──> Sallyport (:9378) ──CDP──> Fortress (:9222)
                              │
                              └── Playwright drives CDP, FastAPI wraps it

Layer	What	Who
Engine	Chromium C++ fingerprint patches (34 patches)	tiliondev/fortress
SDK	Python package to download & launch Fortress	tiliondev (upstream)
REST API	FastAPI + Playwright CDP session management	Sallyport (this project)
Agent skill	Hermes skill for curl-based browsing	Sallyport

How it compares

	Stock Playwright	puppeteer-stealth	Camoufox	Sallyport + Fortress
Spoof layer	none	JS injection	C++ (Firefox)	C++ (Chromium)
toString yields [native code]	n/a	❌	✅	✅
Survives iframe/worker	❌	❌	✅	✅
Engine	Chromium	Chromium	Firefox	Chromium
TLS shape	Chromium	Chromium	Firefox (sticks out)	Chromium
Agent-friendly REST API	❌	❌	❌ (Camofox adds it)	✅ built in
Open source	✅	✅	✅ (MPL)	✅ (MIT)
Worst case Cloudflare Turnstile Managed Challenge	blocked	blocked	blocked	blocked (Fortress limitation)
Worst case Tab open latency	0.8–1.5s	0.8–1.5s	1.0–2.0s	1.1–3.1s (measured, includes CDP setup)

Worst-case numbers are from published benchmarks. We measured the case that matters most: opening a new tab and getting content. Stock Playwright numbers are from the same hardware for reference.

Environment

Variable	Default	Description
SALLYPORT_HOST	0.0.0.0	Server bind address
SALLYPORT_PORT	9378	Server port
FORT_CHANNEL	stable	stable (Chromium 149) or latest (151)
FORT_PORT	9222	Fortress CDP port

Feature flags (kill switches)

Every capability can be disabled at startup via environment variable. These let operators minimize surface area when running Sallyport in restricted environments.

Variable	Default	Effect when set to true
SALLYPORT_DISABLE_SNAPSHOT	(empty)	Blocks all AX tree snapshot endpoints. Tab opens return empty snapshots.
SALLYPORT_DISABLE_AUTO_SNAPSHOT	(empty)	POST /tabs returns only tab_id + url (no snapshot inline). Useful for head-of-line blocking avoidance.
SALLYPORT_DISABLE_JS_EVAL	(empty)	Blocks POST /tabs/{id}/evaluate.
SALLYPORT_DISABLE_SCREENSHOT	(empty)	Blocks POST /tabs/{id}/screenshot.
SALLYPORT_DISABLE_SOURCE	(empty)	Blocks GET /tabs/{id}/source.
SALLYPORT_DISABLE_ACTIONS	(empty)	Blocks click, type, and scroll endpoints.

Disabling a feature makes its endpoints return HTTP 503 with the env var name in the error detail.

Check current flags at runtime:

curl http://localhost:9378/config

Copy for agent

Sallyport is a REST API wrapper around Fortress, an open-source stealth Chromium engine.
It exposes HTTP endpoints so any agent can browse anti-bot-protected sites with curl.

LAUNCH:
  docker run -d --rm --platform linux/amd64 --shm-size=1g -p 9378:9378 fromthescope/sallyport:latest
  curl -X POST http://localhost:9378/browser/start -H "Content-Type: application/json" -d '{}'
  curl -X POST http://localhost:9378/tabs -H "Content-Type: application/json" -d '{"url":"<URL>","wait_ms":3000}'

CONNECT:
  Use the returned tab_id to interact: snapshot, click, type, evaluate.
  curl http://localhost:9378/tabs/{tab_id}/snapshot

RULES:
  1) Do NOT add puppeteer-stealth or JS stealth plugins — Fortress does this in C++.
  2) Do NOT use chromedriver — connect over CDP.
  3) Blocked 90% of the time = IP issue (datacenter), not fingerprint. Use residential proxy.

Full guide: https://github.com/melxusgid/sallyport

License

MIT. The upstream Fortress engine is BSD-3.

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