Unbrowse vs Stagehand: AI SDK vs API Discovery

Stagehand made browser automation smarter by adding AI to the loop. Unbrowse made it faster by removing the browser from the loop. Both tools use intelligence to help agents interact with the web, but they apply that intelligence at completely different layers. Stagehand teaches an AI to drive a browser. Unbrowse teaches an AI that it does not need one.

TL;DR

	Stagehand	Unbrowse
Approach	AI-powered browser automation SDK	API discovery and direct endpoint execution
Speed	Browser-speed + LLM inference (~3,400ms+)	Sub-100ms cached, 950ms average
Token cost	DOM analysis + LLM calls (~8,000+ tokens)	Structured JSON response (~200 tokens)
Auth handling	Manual session management	Auto cookie extraction from real browser profiles
Infrastructure	Needs browser (local or Browserbase cloud)	464KB binary, no browser for cached routes
Pricing	Free (open source), + LLM API costs + optional Browserbase	Free (open source), earns x402 micropayments
Best for	Dynamic UIs, form filling, visual workflows	Data retrieval, API-heavy sites, high-volume agent tasks

What is Stagehand?

Stagehand is an open-source browser automation framework developed by Browserbase that combines AI reasoning with traditional code-based browser control. It provides three core primitives: act() for executing single AI-driven actions, agent() for multi-step automation tasks, and extract() for pulling structured data from pages.

The key insight behind Stagehand is that browser automation should be a hybrid. Some actions are best handled by precise code (navigate to this URL, click this specific button), while others benefit from AI flexibility (find the search box and type a query, extract the main product information from this page). Stagehand lets developers mix both approaches in the same workflow.

Under the hood, Stagehand uses a Chrome DevTools Protocol engine to control the browser while invoking LLMs for decision-making. It includes self-healing actions that adapt when websites change their layout, and an auto-caching system that remembers previous actions to reduce repeated LLM calls. The framework works with local browsers or connects to Browserbase's cloud infrastructure for scale.

Stagehand represents a genuine improvement over raw Playwright or Puppeteer. Natural language commands replace brittle CSS selectors. AI-powered element finding survives layout changes. Structured extraction replaces regex parsing. For developers building browser automation, it is a meaningful step forward.

What is Unbrowse?

Unbrowse starts from a different premise. Rather than making browser automation smarter, it asks: why automate a browser at all when you can call the API directly?

Modern websites are built as thin frontend shells over REST and GraphQL APIs. When you load a product page, your browser makes API calls to fetch product data, pricing, reviews, and recommendations. The rendered HTML is just a visual wrapper around structured data that already exists in JSON form. Browser automation tools, Stagehand included, render that HTML and then use AI to extract data from the rendered output. Unbrowse intercepts the API calls themselves.

The Unbrowse workflow is passive discovery followed by direct execution. When an agent first visits a site, Unbrowse captures all network traffic, identifies API endpoints, reverse-engineers their schemas, and caches the routes. On subsequent visits, it skips the browser entirely and calls those endpoints directly. A shared marketplace lets agents benefit from routes discovered by other agents across thousands of domains.

Benchmarked across 94 live domains in a peer-reviewed study (arxiv.org/abs/2604.00694), Unbrowse achieves a 3.6x mean speedup and 5.4x median speedup over browser-based approaches, with well-cached routes completing in under 100ms.

Key Differences

Architecture

Stagehand operates at the browser layer. It controls a real browser, uses AI to understand what is on the page, and executes actions against the rendered DOM. Every interaction, whether AI-driven or code-driven, goes through the browser pipeline: page load, JavaScript execution, DOM construction, element location, action execution.

Unbrowse operates at the API layer. It understands that the data displayed on a page came from an API call, and it calls that API directly. The browser is used only for initial discovery and as a fallback for sites where API routes have not yet been cached.

Think of it this way: Stagehand is a very smart driver navigating through traffic. Unbrowse found the underground tunnel that bypasses traffic entirely.

Performance

Stagehand inherits browser-speed latency as its baseline: approximately 3,400ms per page interaction. On top of that, it adds LLM inference time for AI-powered actions. When Stagehand's act() or extract() functions invoke an LLM to understand the page and decide what to do, that adds hundreds of milliseconds to seconds of additional latency. The auto-caching system helps on repeated actions, but the first interaction with any new page element always pays the full cost.

Unbrowse cached routes complete in under 100ms. There is no browser load time, no DOM parsing, no LLM inference needed. The route is known, the schema is cached, and the call goes directly to the endpoint. Even uncached routes average 950ms because the browser session only needs to capture network calls, not fully render and AI-analyze the page.

Token Efficiency

Stagehand's AI capabilities require feeding page content to an LLM. When extract() pulls data from a page, the LLM receives a representation of the DOM, typically thousands of tokens, and returns the structured output. When act() decides which element to interact with, the LLM processes the page state. Each AI-powered step consumes LLM tokens for both the page context and the model's reasoning.

Unbrowse returns API responses as-is: structured JSON that requires no LLM interpretation. A typical response is 200 to 500 tokens, and those tokens are the actual data the agent needs, not a page representation that an LLM must parse down. The 40x token reduction means agents can make far more web requests within the same context window and inference budget.

Cost

Stagehand is free and open source, but its operational costs include LLM API calls (for every AI-powered action) plus browser infrastructure (local compute or Browserbase cloud subscription). A workflow that makes 100 AI-powered browser actions per hour incurs both browser compute and LLM inference costs.

Unbrowse is free and open source with a 464KB runtime. Cached route execution costs are negligible. No LLM calls are needed for known routes. The x402 micropayment system means agents that contribute route discoveries to the marketplace can earn credits, creating a self-sustaining economic model.

Authentication

Stagehand relies on manual session management for authentication. You handle login flows, cookie persistence, and session state through your automation scripts or through Browserbase's session management features.

Unbrowse automatically extracts authentication cookies from your real browser profiles. If you are logged into a site in Chrome or Firefox, Unbrowse uses those credentials when calling APIs. It supports 15+ SSO providers and maintains per-domain auth profiles. No login scripting required.

When to Use Stagehand

Stagehand is the right choice when:

• You need to interact with dynamic UIs: multi-step forms, drag-and-drop interfaces, rich web applications
• Visual context matters: the AI needs to see and understand the page layout to make decisions
• Sites have no stable APIs: some older or highly dynamic sites do not expose clean API endpoints
• You need self-healing automation: when site layouts change frequently and you want the AI to adapt
• Complex multi-step workflows: where AI reasoning about page state is essential to navigation

When to Use Unbrowse

Unbrowse is the clear choice when:

• Data retrieval is the primary goal: getting structured data from websites, not interacting with UIs
• Speed is critical: sub-100ms vs multi-second response times
• Token budget is limited: 40x fewer tokens per action
• High-volume workflows: hundreds or thousands of web requests per hour
• Multi-agent systems: shared route marketplace means agents build on each other's discoveries
• MCP integration: Unbrowse serves as an MCP server, making it the default web layer for any AI framework

Getting Started with Unbrowse

npm install -g unbrowse
unbrowse setup

Resolve data from any URL:

unbrowse resolve "get user profile" --url https://example.com/user/123

No browser setup, no LLM configuration, no cloud account required.

The Bottom Line

Stagehand and Unbrowse both use intelligence to improve how agents interact with the web, but they apply it at different layers. Stagehand adds AI to browser automation: smarter element finding, natural language actions, self-healing scripts. It makes the browser a better tool. Unbrowse applies intelligence to bypass the browser entirely: automatic API discovery, route caching, shared marketplace.

The distinction matters because it determines your scaling curve. Stagehand's costs grow with usage since every action needs a browser and potentially an LLM call. Unbrowse's costs decrease with usage since every discovered route makes future requests free and instant.

For agents that need to interact with complex visual UIs, Stagehand is a genuine improvement over raw browser automation. For agents that need structured data from the web at speed and scale, Unbrowse removes an entire layer of unnecessary overhead. The web already has APIs. Unbrowse just finds them for you.