Browserbase + Stagehand drive AI browser agents into login-walled, JS-heavy sites. UnifAPI is HTTP endpoints for public data. Pick by access boundary.

Browserbase is managed headless-browser infrastructure for AI agents; Stagehand is its open-source automation framework that turns natural-language instructions (act / extract / observe / agent) into browser actions. Together they're the right answer for login-walled, JS-heavy, or interactive workflows. UnifAPI is HTTP endpoints for public data — no browser, no session, no login. The line between them is the access boundary, not the platform list.

What each one is

Browserbase rents you a managed headless browser via API, complete with proxies, captcha solving, session replay, and prompt observability. Stagehand sits on top: an SDK where you write code like `page.act("click the sign-in button")` and Stagehand translates that into the right DOM operations using an LLM. Together they're the production stack for AI agents that have to drive a browser like a human would.

UnifAPI is the layer below the browser. A call to /v1/reddit/search hits Reddit's data tier directly and returns structured JSON. There's no DOM, no JS execution, no rendering, no flaky selectors. The trade is that UnifAPI only sees what the public platform makes available — anything behind a login is out of scope.

The access boundary

If the data your agent needs requires a logged-in session — your user's Gmail inbox, their HubSpot dashboard, their bank statements, a competitor's private analytics page — you need a browser agent. Browserbase + Stagehand are built for this. The agent logs in (with the user's credentials, scoped to the session), navigates, extracts, and returns. The browser is the boundary.

If the data is public — tweets, public Reddit threads, search results, news articles, YouTube videos — a browser is overkill. You're paying for compute, latency, and complexity you don't need. UnifAPI hits the platform's data tier directly. Same data, lower cost, lower latency, no flakiness.

Pricing model

Browserbase: $0/month for 1 free browser hour. $20/month Developer plan: 100 hours. $99/month Startup plan: 500 hours, 100 concurrent browsers. Overage: $0.10 / browser-hour. On top of that, Stagehand burns LLM tokens — community reports suggest $50-200/day in model fees for workloads running 10,000 extractions/day.

UnifAPI: $0.001 per record returned, no compute charge, no LLM tokens on our side. 1,000 free records / month. The same 10,000-extraction/day workload, if it can be served from public-data endpoints, runs at $10/day with no LLM fees layered on top.

The pricing models are incomparable on purpose: browser-hour pricing is the right unit for sessions that can take 30 seconds each; per-record pricing is the right unit for direct HTTP calls that return in 200ms.

Latency and reliability

Browser agents are slow and brittle, by physics rather than design. A single Stagehand session that opens a page, clicks, and extracts is typically 10-30 seconds. Selectors break when the upstream UI shifts; the LLM-driven `act()` recovers gracefully but still costs tokens. Reliability is the engineering challenge of the entire category.

HTTP API calls round-trip in 100-500ms, return predictable JSON, and don't break when the upstream rewrites their CSS. Reliability comes from one place: the gateway's reshape layer.

When Browserbase / Stagehand wins

Pick Browserbase + Stagehand when the data is behind a login, behind aggressive JS, or behind a multi-step interactive flow. "Sign into the user's CRM and pull this week's deals," "log into the airline portal and rebook the cancelled flight," "navigate the SaaS dashboard the user just connected" — all browser-agent territory.

When UnifAPI wins

Pick UnifAPI when the data is public and you'd rather not operate a browser stack. Social platforms, search results, public scrape, news — all behind HTTP endpoints with one key, one shape, $0.001 per record. Browse the live catalog at unifapi.com/apis, pricing at unifapi.com/pricing, MCP setup at unifapi.com/mcp.

Using both

Production agents typically draw the line where authentication starts. UnifAPI for the open-web half (find what's trending, monitor a brand, search the news), Browserbase + Stagehand for the OAuth-or-login-walled half (act on the user's own SaaS accounts). The two don't overlap and don't compete; they meet at the auth boundary and stay there.