Project Mariner vs Stagehand
Project Mariner vs Stagehand: side-by-side comparison of two computer-use & desktop agents systems — architecture, taxonomy, license, pricing, MCP/A2A support, and direct edges.
Cost & capability
| Project Mariner | Stagehand | |
|---|---|---|
| Capability band | competent | competent |
| Capability composite | 73 | 58 |
| Cost tier | mid | free |
| $/Mtok input | — | 0 |
| $/Mtok output | — | 0 |
| Use cases | Scoped Agentic | Scoped Agentic, Code Generation Focused |
Where they differ (15)
Rows where both sides have data and the values disagree — the shortlist of dimensions that actually distinguish these two systems.
| Project Mariner | Stagehand | |
|---|---|---|
| Capability composite | 73 | 58 |
| Cost tier | mid | free |
| Use cases | Scoped Agentic | Scoped Agentic, Code Generation Focused |
| Type | Google DeepMind browser-agent (research preview) | OSS browser-automation framework (Browserbase OSS) |
| Created | 2024-12 | 2024 (Browserbase release) |
| Pricing | Bundled with Gemini Advanced ($19.99/mo) | OSS free; Browserbase Cloud handles runtime |
| Funding | Google DeepMind parent (Alphabet) | Maintained by Browserbase ($40M Series B Q4 2024; Kleiner Perkins) |
| Backend storage | Google-managed session state | Local Playwright state; Browserbase-managed when cloud-hosted |
| Deployment | Chrome extension + Google Cloud | Library — runs anywhere Playwright runs; Browserbase Cloud for managed |
| API surface | Chrome extension; underlying Gemini 2.0 API | TS API (act/extract/observe); npm: @browserbasehq/stagehand |
| Multi-tenancy | Single-tenant per Google account | Per-process in OSS; per-tenant in Browserbase Cloud |
| MCP | searched not found | Composes with Browserbase MCP server |
| A2A | Google's own A2A protocol — likely first-party compatible | searched not found |
| Optimised for | Gemini 2.0-powered Chrome agent | Playwright-replacement with AI verbs (act / extract / observe) |
| Anti-fit | Research preview only; Chrome only; Gemini Advanced tier | TS-only; not a finished agent — caller wires logic; tied closely to Browserbase ecosystem |
At a glance
| Project Mariner | Stagehand | |
|---|---|---|
| Section | Computer-use & desktop agents | Computer-use & desktop agents |
| Tier | T1 | T1 |
| Type | Google DeepMind browser-agent (research preview) | OSS browser-automation framework (Browserbase OSS) |
| Created | 2024-12 | 2024 (Browserbase release) |
| Latest release | — | v2.x; active monthly releases (npm: @browserbasehq/stagehand) |
| License | — | MIT |
| GitHub | — | github.com/browserbase/stagehand — 9k+ stars |
| Pricing | Bundled with Gemini Advanced ($19.99/mo) | OSS free; Browserbase Cloud handles runtime |
| Funding | Google DeepMind parent (Alphabet) | Maintained by Browserbase ($40M Series B Q4 2024; Kleiner Perkins) |
| Backend storage | Google-managed session state | Local Playwright state; Browserbase-managed when cloud-hosted |
| Deployment | Chrome extension + Google Cloud | Library — runs anywhere Playwright runs; Browserbase Cloud for managed |
| API surface | Chrome extension; underlying Gemini 2.0 API | TS API (act/extract/observe); npm: @browserbasehq/stagehand |
| Multi-tenancy | Single-tenant per Google account | Per-process in OSS; per-tenant in Browserbase Cloud |
| MCP | searched not found | Composes with Browserbase MCP server |
| A2A | Google's own A2A protocol — likely first-party compatible | searched not found |
| OpenTelemetry | searched not found | searched not found |
| Optimised for | Gemini 2.0-powered Chrome agent | Playwright-replacement with AI verbs (act / extract / observe) |
| Anti-fit | Research preview only; Chrome only; Gemini Advanced tier | TS-only; not a finished agent — caller wires logic; tied closely to Browserbase ecosystem |
Taxonomy
| Axis | Project Mariner | Stagehand |
|---|---|---|
| storage | kv | file |
| retrieval | injection | injection |
| persistence | session | session |
| update | agent-controlled | agent-controlled |
| unit | turn | document |
| governance | opaque | inspectable |
| conflict | stateless | human-arbitrate |
Pros & cons
Project Mariner
Pros: Strong WebVoyager numbers; Google distribution; A2A first-party adjacency.
Cons: Research preview; Chrome / Gemini Advanced tier; closed source.
Stagehand
Pros: Browserbase-backed OSS; clean act/extract/observe primitive; growing TS-agent ecosystem.
Cons: TS-only (no Python parity); ties best with Browserbase Cloud (vendor adjacency).