Tandem Browser
Tandem Browser is an open-source, local-first browser that lets AI agents work through the user's browser session, including tabs, cookies, and the DOM.
What Tandem Browser is
Tandem Browser is an open-source, local-first browser that lets AI agents work through the user's browser session, including tabs, cookies, and the DOM. Agents can access the accessibility tree, rendered page structure, network requests, console output, and DevTools. If an agent encounters a CAPTCHA, an unclear form, or a decision needing human judgment, it pauses and asks the user for help. MCP- or HTTP-speaking agents can connect locally or remotely over a private Tailscale network, with separate workspaces and tab locks to avoid conflicts. Its API documentation lists more than 280 HTTP endpoints and 257 MCP tools, using bearer-token authentication. The maker says Tandem has no cloud backend, subscription, or telemetry, and that browsing data stays on the user's machine unless shared elsewhere. It can run offline with a local model such as Ollama or LM Studio. The free MIT-licensed browser is in developer preview and supports macOS Apple Silicon, Windows 11 x64, and Linux on a best-effort basis. It also lists workspaces, extensions, bookmarks, history, a local password vault, and sidebar apps including Telegram, WhatsApp, Discord, Slack, Gmail, Calendar, Instagram, and X.
Good
- Open source under the MIT license.
- No cloud backend, subscription, or telemetry, per maker.
- Agents can pause for user help.
- Supports offline use with a local model.
- Includes browser workspaces, extensions, and bookmarks.
Watch out
- The product is in developer preview.
- Linux support is best-effort.
- Support is directed to GitHub Discussions and issues.
Who it suits
Tandem Browser is aimed at AI power users, MCP builders, privacy-minded operators, and teams exploring browser agents. It may also suit users who want local browser data handling and can work with a developer-preview product.
Verdict
Tandem Browser connects agents to a local browser session while leaving control with the user for difficult steps. Its developer-preview status and best-effort Linux support are worth considering.
Plans and prices
From Tandem Browser's own pricing page, checked 30 Sep 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free | Free | Free and open source · no subscription |
The facts
Each one read from Tandem Browser's own pages, with the date it was checked.
What it does
- Agent connections
- Agents can connect on the same machine or remotely over a private Tailscale network; each agent can have its own workspace, with tab locks to prevent conflicts.checked 30 Sep 2026
- API
- The API page documents more than 280 HTTP endpoints and 257 MCP tools, with bearer-token authentication.checked 30 Sep 2026
- Audience
- The maker describes the product as aimed at AI power users, MCP builders, privacy-minded operators, and teams exploring browser agents.checked 30 Sep 2026
- Data handling
- The FAQ says there is no Tandem Browser cloud backend, subscription, or telemetry, and that browsing data stays on the user's machine unless they choose to send it elsewhere.checked 30 Sep 2026
- Human handoff
- When an agent encounters a CAPTCHA, unclear form, or judgment call, it pauses and asks the user for help.checked 30 Sep 2026
- License and stage
- The site identifies Tandem Browser as MIT licensed and in developer preview.checked 30 Sep 2026
- Model integrations
- The maker says agents that speak MCP or HTTP can connect, including Claude, GPT, Gemini, OpenClaw, Ollama, LM Studio, and custom scripts.checked 30 Sep 2026
- Offline use
- The FAQ says Tandem Browser can run fully offline when used with a local model such as Ollama or LM Studio.checked 30 Sep 2026
- Page access
- Agents can work with the accessibility tree, rendered DOM, network requests, console output, and DevTools.checked 30 Sep 2026
- Product
- Tandem Browser is an open-source, local-first browser where AI agents share the user's browser session, tabs, cookies, and DOM.checked 30 Sep 2026
- Security
- The maker describes an eight-layer security pipeline with an 811K-plus-entry blocklist, YARA-style rules, AST fingerprinting, entropy detection, and 51 automated tests.checked 30 Sep 2026
- Sidebar integrations
- The repository lists Telegram, WhatsApp, Discord, Slack, Gmail, Calendar, Instagram, and X as sidebar apps.checked 30 Sep 2026
- Support
- The maker directs users to GitHub Discussions for questions and troubleshooting, and GitHub issues for bugs and concrete feature requests.checked 30 Sep 2026
Where it runs
- Browser features
- The maker lists workspaces, extensions, bookmarks, history, a local password vault, and sidebar apps among its daily-driver browser features.checked 30 Sep 2026
- Platforms
- The FAQ lists macOS Apple Silicon and Windows 11 x64 as supported, with Linux described as best-effort; it says macOS builds are signed and notarized while Windows builds are unsigned.checked 30 Sep 2026
