VulpineOS
Open-source operator runtime with C++ stealth + execution patches, self-hosted, billed only on the LLM and infrastructure you bring.
Open runtime vs hosted Chrome.
Browserbase runs Chrome in their cloud and bills per session-minute. VulpineOS is an open-source operator runtime you self-host, with a Camoufox base and execution primitives Chrome can't ship.
Browserbase
Managed Chrome-as-a-service. You write Playwright code, they run the browser, you pay per session-minute.
browserbase.com ↗Feature comparison
Grouped by what you actually evaluate when picking a runtime for AI browser agents — foundation, execution, identity, density, cost.
Browser foundation
| Feature | VulpineOS | Browserbase |
|---|---|---|
| Source code is open | — | |
| Self-hostable | — | |
| Browser engine | Firefox 146 (Camoufox) | Chromium |
| Engine-level stealth patches | PARTIAL | |
| Run locally on your laptop | — |
Execution layer
| Feature | VulpineOS | Browserbase |
|---|---|---|
| C++ injection-proof a11y filter | — | |
| Action-Lock page freeze (nsDocShell) | — | |
| Token-optimised DOM export (>90% reduction) | — | |
| Loop detector for repeated tool calls | — |
Identity layer
| Feature | VulpineOS | Browserbase |
|---|---|---|
| Persistent identities across sessions | PARTIAL | |
| BrowserForge fingerprint pipeline | PARTIAL | |
| BYO proxy pool with auto-rotation | PARTIAL | |
| Trust-warming background service | — |
Density layer
| Feature | VulpineOS | Browserbase |
|---|---|---|
| Pre-warmed context pool | PARTIAL | |
| Per-context memory limits | — | |
| Multi-agent orchestration built in | — | |
| Operator console for hundreds of agents | — |
Cost model
| Feature | VulpineOS | Browserbase |
|---|---|---|
| Pay per session-minute | — | |
| Pay only for LLM + your own infra | — | |
| Free tier | Self-host any volume | Limited |
Comparison reflects publicly-available product documentation as of May 2026. We update this page when vendors ship material changes.
Pricing model
VulpineOS
Runtime is MPL 2.0 — free to self-host at any scale. The only costs are your infrastructure and your LLM usage. A managed cloud is on the roadmap; current offering is open-source self-host.
Browserbase
Per session-minute pricing on top of plan tiers. Costs scale with both how long sessions are open and how many run concurrently. Browser concurrency is gated by plan.
When each one is the right choice
Pick VulpineOS when
- You need engine-level guarantees. Action-lock and the injection filter are C++ patches. They aren't features you can add to a hosted Chrome — they require shipping a custom browser binary.
- Density is part of your unit economics. If your agent workload runs hundreds of parallel sessions for hours per identity, per-minute billing dominates. Self-host removes that variable.
- You want a consolidated runtime. Operator console, MCP toolbelt, agent bus, recording, and session pause/resume are first-class. You don't bolt them on with separate vendors.
Pick Browserbase when
- You don't want to operate infrastructure. If running a fleet of headless browsers is not your team's competence, a managed service removes a real ops burden.
- You want managed Chrome specifically. Some workloads target Chrome-only behaviour (extensions, specific DevTools features). VulpineOS is Firefox-based today.
- Stagehand fits your agent stack. Browserbase ships Stagehand as their agent layer. If you've already built around it, the integration cost is sunk.
Interop / migration
Browserbase exposes Playwright-compatible endpoints. VulpineOS does too, via the Foxbridge CDP server — Playwright scripts you wrote against Browserbase will run against VulpineOS with a connection-string change. You don't have to rewrite anything to evaluate side-by-side.
FAQ
- Is VulpineOS a drop-in replacement for Browserbase?
- API-shape, mostly yes — both speak Playwright. Operationally, no — VulpineOS is self-hosted today, so you trade per-minute billing for running your own infrastructure.
- Can I use Stagehand-style agent code with VulpineOS?
- VulpineOS ships its own MCP toolbelt and agent runtime. Stagehand-compatible bindings aren't shipped, but the underlying browser is Playwright-driveable, so you could port the orchestration layer.
- Why Firefox instead of Chrome?
- Camoufox (our Firefox base) accepts engine patches we can ship in unified diffs. Chromium's IPC layer makes equivalent action-lock and injection-filter patches harder to maintain across upstream merges. Detection coverage on Firefox is also weaker than on Chrome — the bot-detection vendors have spent more time pattern-matching Chromium automation than Gecko automation.
Try it side by side
The fastest way to settle this is a 30-minute side-by-side. VulpineOS is open source — clone, run, point your existing automation at it. We'll happily help you size the comparison if you want.