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Show HN: Stagehand – an open source browser automation framework powered by AI
Hi HN! I’m Anirudh — longtime lurker, first time poster, and I couldn’t be more excited to show you Stagehand.
Stagehand is a TypeScript project that extends Playwright with three simple AI methods — act, extract, and observe. We’d love for you to try it out using the command below:
npx create-browser-app --example quickstart
Here’s a sample workflow:
const stagehand = new Stagehand();
await stagehand.init();
// Stagehand overrides the Playwright Page and Context classes
const { page, context } = stagehand
await page.goto("instadash.com") // Regular Playwright
// Take action on the page
await page.act({ action: "click on taqueria cazadores" })
// Extract relevant data from the page
const { price } = await page.extract({
instruction: "extract the price of the super burrito",
schema: z.object({
price: z.number()
})
})
We built Stagehand because we loved building browser automations using Playwright and Selenium, but we grew frustrated at how cumbersome it is to just get started and write simple browser automations. These frameworks, while incredibly powerful, are built for QA testing and are thus notoriously prone to fail if there are minor changes in the UI or underlying DOM structure.
The goal of Stagehand is twofold:
1. Make browser automations easier to write
2. Make browser automations more resilient to DOM changes.
We were super energized by what we’ve been seeing with vision-based computer use agents. We think with a browser, you can provide even richer data by leveraging the information in the DOM + a11y tree in addition to what’s rendered on the page. However, we didn’t want to go so far as to build an agent, since we wanted fine-grained control over each step that an agent can take.
Therefore, the happy medium we built was to extend the existing powerful functionalities of Playwright with simple and extensible AI APIs that return the decision-making power back to the developer at each step.
Check out our docs: https://docs.stagehand.dev https://docs.stagehand.dev
We’d love for you to join and give us feedback on Slack as well: https://stagehand.dev/slack https://stagehand.dev/slack
- righthand 2y agoI’m curious how this compares to playwrights already built in codegen: https://playwright.dev/docs/codegen-intro https://playwright.dev/docs/codegen-intro Is a chat bot easier to reiterate a test?
- hackgician 2y agoPlaywright codegen is incredibly powerful, but still pretty brittle. Its DOM selectors are still hardcoded, so you run the risk of Playwright selecting an unsustainable DOM selector. With Stagehand, the code is self-healing since it's dynamically generating Playwright every time, making it much more resilient to minor DOM changes
- kevmo314 2y agoHow do you avoid this becoming horrendously expensive per run? Are the results cached if the DOM doesn't change?
- hackgician 2y agoThe purpose of using Playwright is to basically write deterministic workflows in deterministic automation code. We have basic prompt caching right now that works if the DOM doesn't change (as you mention), but also the best way to reduce token cost is to reduce reliance on AI itself. You have the most control over how much you want to rely on AI v. how much you want to write repeatable Playwright code.
- kevmo314 2y agoThat seems like a pretty tough sell over bare playwright. Unless the UI is constantly changing, the cost of verifying tests are still successful seems like it would eclipse the cost of an engineer maintaining the test pretty quickly. Some minimal model that could be run locally and specifically tuned for this purpose might be pretty fruitful here compared to delegating out to expensive APIs.
- hackgician 2y agoDefinitely a very interesting problem we're trying to dig deep into. We'd welcome any PRs here as well from the community :)
- 2y ago
- BrandiATMuhkuh 2y agoCongratulations. This is super cool. I often thought E2E testing should be done with AI. What I want is that the functionality works (e.g.: login, then start an assignment) without the need to change the test each time the UI changes.
- hackgician 2y agoThanks so much! Sounds like Stagehand is a perfect fit; would love to hear your thoughts :)
- mpalmer 2y agoThis looks very cool and makes a lot of sense, except for the idea that it should take the place of Playwright et al. Personally I'd love to use this as an intermediate workflow for producing deterministic playwright code, but it looks like this is intended for running directly. I don't think I could plausibly argue for using LLMs at runtime in our test suite at work...
- hackgician 2y agoInteresting, thanks for the feedback! By "taking the place of Playwright," we don't mean the AI itself is going to replace Playwright. Rather, you can continue to use existing Playwright code with new AI functionalities. In addition, we don't really intend for Stagehand to be used in a test suite (though you could!). Rather, we want Stagehand to assist people who want to build web agents. For example, I was using headless browsers earlier in 2024 to do real-time RAG on e-commerce websites that could aggregate results for vibes-based search queries. These sites might have random DOM changes over time that make it hard to write sustainable DOM selectors, or annoying pop-ups that are hard to deterministically code against. This is the perfect use for Stagehand! If you're doing QA on your own site, then base Playwright (as you mention) is likely the better solution
- andrewmcwatters 2y agoIt seems to me like Selenium would have been a more appropriate API to extend from, then. Playwright, despite whatever people want it to be otherwise, is explicitly positioned for testing, first. People in the browser automation space consistently ignore this, for whatever reason. Though, it's right on their site in black and white.
- hackgician 2y agoAppreciate the feedback. Our take is that Playwright is an open-sourced library with a lot of built-in features that make building with it a lot easier, so it's definitely an easier starting point for us
- pryelluw 2y agoCan it be adapted to use ollama? Seems like a good tool to setup locally as a navigation tool.
- hackgician 2y agoYes, you can certainly use Ollama! However, we strongly recommend using a more beefed up model to get sustainable results. Check out our external_client.ts file in examples/ that shows you how to setup a custom LLMClient: <https://github.com/browserbase/stagehand/blob/main/examples/external_client.ts https://github.com/browserbase/stagehand/blob/main/examples/...>
- fidotron 2y agoIt doesn’t look like accessing the llmclient for this is possible for external projects in the latest release, as that example takes advantage of being inside the project. (At least working through the quick start guide).
- hackgician 2y agoWe accidentally didn't release the right types for LLMClient :/ However, if you set the version in package.json to "alpha", it will install what's on the main branch on GitHub, which should have the typing fix there
- fidotron 2y agoYeah I saw it was a recent change in your GitHub and was happily running your examples. To be honest I took about 2 minutes of playing around to get annoyed with the inaccuracies of the locally hosted model for that, so I get why you encourage the other approaches.
- jsdalton 2y agoDoes it operate by translating your higher level AI methods into lower level Playwright methods, and if so is it possible to debug the actual methods those methods were translated to? Also is there some level of deterministic behavior here or might every test run result in a different underlying command if your wording isn’t precise enough?
- hackgician 2y agoIt's a little hacky, but we have a method in the act() handler called performPlaywrightMethod that takes in a playwright method + xpath and executes the playwright method on the xpath. There's definitely a lot of room for improvement here, and we're working on making observe() fill those gaps. I think observe() aims to be like GitHub Copilot's gray suggested text that you can then confirm in a secondary step; whereas act() takes on a more agentic workflow that you let the underlying agent loop make decisions on your behalf
- TibbityFlanders 2y ago[dead]
- zanesabbagh 2y agoHave been on the Slack for a while and this crew has had an insane product velocity. Excited to see where it goes!
- hackgician 2y agoThanks so much Zane!!
- dchuk 2y agoThis looks awesome. What I would love to see either as something leveraging this, or built in to this, is if you prompt stagehand to extract data from a page, it also returns the xpath elements you'd use to re-scrape the page without having to use an LLM to do that second scraping. So basically, you can scrape new pages never before seen with the non-deterministic LLM tool, and then when you need to rescrape the page again to update content for example, you can use the cheaper old-school scraping method. Not sure how brittle this would be both going from LLM version to xcode version reliably, or how to fallback to the LLM version if your xcode script fails, but overall conceptually, being able to scrape using the smart tools but then building up basically a library of dumb scraping scripts over time would be killer.
- hackgician 2y agoYeah, I think someone opened a similar issue on GitHub: https://github.com/browserbase/stagehand/issues/389 https://github.com/browserbase/stagehand/issues/389 Repeatability of extract() is definitely super interesting and something we're looking into
- 9dev 2y agoCache the response for a given query-page hash pair maybe? So the LLM will only be consulted when the page content hash changes, the previous answer be reused otherwise
- matsemann 2y agoAgree. The worst part of integration tests are how brittle they often are. I don't want to introduce yet another thing that could give false test errors. But of course, the way it works now could also help reduce the brittleness. With an xpath or selector, it quickly breaks when the design changes or things are moved around. With this, it might overcome this. So tradeoffs, I guess.
- ushakov 2y agothere’s also llm-scraper: https://github.com/mishushakov/llm-scraper https://github.com/mishushakov/llm-scraper disclaimer: i am the author
- jerrygoyal 2y agowow. It's like cursor vs vscode movement but for browser automation and scrapping. Kudos to the author. Are there any other similar tools?
- andrethegiant 2y agohttps://crawlspace.dev https://crawlspace.dev has a similar LLM-aware scraping where you can pass a Zod object and it’ll match the schema, but is available as a PaaS offering with queueing / concurrency / storage built in [disclaimer: I’m the founder]
- hackgician 2y agoThanks so much! Crawlspace is pretty sick too, as is Integuru. A lot of people have different takes here on the level of automation to leave up to the user. As a developer building for developers, I wanted to meet in the middle and build off an existing incumbent that most people are likely familiar with already
- insdev12 2y agoYea Integuru is pretty cool: https://github.com/Integuru-AI/Integuru https://github.com/Integuru-AI/Integuru
- jameslk 2y agoCool to see another open source AI browser testing project! There’s a couple of others I’ve heard of as well: Skyvern: https://github.com/Skyvern-AI/skyvern https://github.com/Skyvern-AI/skyvern Shortest: https://github.com/anti-work/shortest https://github.com/anti-work/shortest I’d love to hear what makes Stagehand different and pros/ cons. Of course, I have no complaints to see more competition and open source work in this space. Keep up the great work!
- hackgician 2y agoYes! These are both phenomenal projects, and kudos to their authors as well. Stagehand is different in that it makes fine-grained control a first-class citizen. Often times, you want to control the exact steps a web agent takes. Our experience using other tools was that the only control you have over these steps in other tools is in the natural language prompt. However with Stagehand, because it's an extension of Playwright, it allows you to confirm each step of the underlying agent's workflow, making it the most customizable option for engineers who want/need that
- bluelightning2k 2y agoDoes this open up the possibility of automating an existing open browser tab? (Instead of a headless or specifically opened instance of chrome?)
- namanyayg 2y agoAfaik no. But if it's access to authenticated resources that you want, you can do so by copying over cookies.
- hackgician 2y agoYes^ this is what we suggest. Stagehand is meant to execute isolated tasks on browsers; we support using custom contexts (cookies) with the following command: npx create-browser-app --example persist-context
- its_down_again 2y agoHave you looked into agentic chrome extensions like MultiOn? They use a similar class of AI model, but work on top of existing open browser tabs.
- z3t4 2y agoMy kneejerk reflex: "create-browser-app" is a very generic name, should just have called it "stagehand"
- fbouvier 2y agoHey Anirudh, Stagehand looks awesome, congrats. Really love the focus on making browser automations more resilient to DOM changes. The act, extract, and observe methods are super clean. You might want to check out Lightpanda (https://github.com/lightpanda-io/browser https://github.com/lightpanda-io/browser). It's an open-source, lightweight headless browser built from scratch for AI and web automation. It's focused on skipping graphical rendering to make it faster and lighter than Chrome headless.
- TheTaytay 2y agoLightpanda does look promising, but this is an important note from the readme: " You should expect most websites to fail or crash."
- fbouvier 2y agoYou're absolutely right, the 'most websites will fail' note is there because we're still in development, and the browser doesn't yet handle the long tail of web APIs. That said, the architecture's coming together and the performance gains we're seeing make us excited about what's possible as we keep building. Feedback is very welcome, especially on what APIs you'd like to see us prioritize for specific workflows and use cases.
- qeternity 2y agoI don't really follow: a lot of the fragility of web automation comes from the programmatic vs. visual differences, which VLMs are able to overcome. Skipping the graphical rendering seems to be committing yourself to non-visual hell. The web isn't made for agents and automation. It's made for people.
- hackgician 2y agoYes and no. Getting a VLM to work on the web would definitely be great, but it comes with its own problems, mainly around developing and acting on bounding boxes. We have vision as a default fallback for Stagehand, but we've found that the screenshot sent to the VLM often has to have pre-labeled elements on it. More notably, the screenshot with everything prelabeled leads to a cluttered and unusable image to process. Not pre-labeling runs the risk of missing important elements. I imagine a happy medium where the DOM+a11y tree can be used for candidate generation to a VLM. Solely depending on a VLM is indeed reminiscent of how humans interact with the web, but when a model thrives with more data, why restrict the data sent to the model?
- asar 2y agoThis looks really cool, thanks for sharing! I recently tried to implement a workflow automation using similar frameworks that were playwright or puppeteer based. My goal was to log into a bunch of vendor backends and extract values for reporting (no APIs available). What stopped me entirely were websites that implemented an invisible captcha. They can detect a playwright instance by how it interacts with the DOM. Pretty frustrating, but I can totally see this becoming a standard as crawling and scraping is getting out of control.
- hackgician 2y agoThanks so much! Yes, a lot of antibots are able to detect Playwright based on browser config. Generally, antibots are a good thing -- I think in the future, as web agents become more popular, I'd imagine a fruitful partnership to prevent misuse if it's coming from a trusted web agent v. an unknown one
- fredtalty5 2y ago[dead]
- CyberDildonics 2y agoPeople must be excited for this since a lot of people are commenting for the first time in months or years to say how much they love it. Some people liked it so much they commented for the first time ever to say how great it is.
- ramesh31 2y agoThis is 100% the future of UI testing. The dream of BDD and Gherkin can be fully realized now that the actual test code writing/maintenance portion is completely taken care of.
- CyberDildonics 2y agoThis thing that was just released is the future of UI testing? I usually just use the UI to test it.
- ramesh31 2y ago>This thing that was just released is the future of UI testing? The general idea of it, yes. No one will be writing selector based tests by hand anymore in a couple years.
- mkagenius 2y agoAnd here I was in trenches with 2 upvotes with Show HN for https://github.com/BandarLabs/clickclickclick https://github.com/BandarLabs/clickclickclick
- owebmaster 2y agoAny attempt on doing something similar but as a browser extension?
- hackgician 2y agoThat's definitely compelling, but not something we have in mind for the immediate future. Let me know if you end up building something here!
- temuze 2y agoI'm currently working on it :) See you in two weeks I hope
- owebmaster 2y agoanything we can see already?
- tomatohs 2y agoCool! Before building a full test platform for testdriver.ai we made a similar sdk called Goodlooks. It didn't get much traction, but will leave it here for those interested: https://github.com/testdriverai/goodlooks https://github.com/testdriverai/goodlooks
- hackgician 2y agoThis is sick! Starred, thanks for sharing :)
- xingwu 2y agoCan the script be compiled into actual DOM operations so that we don't need LLM for every run？
- arvindsubram 2y agoThe easiest way to programmatically browse the web!!
- hackgician 2y agoThanks so much!! Appreciate the feedback
- sparab18 2y agoI've been playing around with Stagehand for a minute now, actually a useful abstraction here. We build scrapers for websites that are pretty adversarial, so having built in proxies and captcha is delightful. Do you guys ever think you'll do a similar abstraction for MCP and computer use more broadly?
- hackgician 2y agoThanks so much! Our Stagehand MCP server actually won Anthropic's Claude MCP hackathon :) Check it out: https://github.com/browserbase/mcp-server-browserbase/tree/main/stagehand https://github.com/browserbase/mcp-server-browserbase/tree/m... We're working on a better computer use integration using Stagehand, def a lot of interesting potential there
- jimmySixDOF 2y agointeresting and hope to see this improve with open source GUI Agent vision model projects like OS-Atlas https://osatlas.github.io/ https://osatlas.github.io/
- chw9e 2y agoThe MCP server is useful, I built a demo of converting bug reports into Playwright tests using it - https://qckfx.com/demo https://qckfx.com/demo
- hackgician 2y agoWhoa -- this is so cool! Is this open source? Would love to check it out
- chw9e 2y agoNo, but happy to chat about it. My email is chris.wood@qckfx.com
- vitalets 2y agoLooks interesting. I know about the similar project - https://zerostep.com https://zerostep.com. Is it basically the same?
- fasten 2y agocool extension to playwright! how effective are the ai methods in handling dynamic ui changes?