This 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.
I've been on a similar thread w my own crawler project -- conceptually at least, since I'm intentionally building as much of it by hand as possible... Anyway, after a lot of browser automation, I've realized that it's more flexible and easier to maintain to just use a DOM polyfill server-side and then use the client to get raw HTML responses wherever possible. (And, in conversations about similar LLM-focused tools, that if you generate parsing functions you can reuse, you don't necessarily need an LLM to process your results.)
I'm still trying to figure out the boundaries of where and how I want to scale that out into other stuff -- things like when to use `page` methods directly, vs passing a function into `page.evaluate`, vs other alternatives like a browser extension or a CLI tool. And I'm still needing to work around smaller issues with the polyfill and its spec coverage (leaving me to use things like `getAttribute` more than I would otherwise). But in the meantime it's simplified a lot of ancillary issues, like handling failures on my existing workflows and scaling out to new targets, while I work on other bot detection issues.
Yeah, I think someone opened a similar issue on GitHub: https://github.com/browserbase/stagehand/issues/389
Repeatability of extract() is definitely super interesting and something we're looking into
Cache 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
Agree. 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.
there’s also llm-scraper: https://github.com/mishushakov/llm-scraper
disclaimer: i am the author
This 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...
It's funny you mentioned "deterministic Playwright code," because in my experience, that’s one of the most frustrating challenges of writing integration tests with browser automation tools. Authoring tests is relatively easy, but creating reliable, deterministic tests is much harder.
Most of my test failures come down to timing issues—CPU load subtly affects execution, leading to random timeouts. This makes it difficult to run tests both quickly and consistently. While proactive load-testing of the test environment and introducing artificial random delays during test authoring can help, these steps often end up taking more time than writing the tests themselves.
It would be amazing if tools were smart enough to detect these false positives automatically. After all, if a human can spot them, shouldn’t AI be able to as well?
I was working on a side project over the holidays with the (I think) same idea as mpalmer imagined there too (though my project wouldn't be interested to him either, because my goal wasn't automating tests)
Basically, the goal would be to do it like with screenshot regression tests: basically you get 2 different execution phases: - generate - verify
And when verify fails in CI, you can automatically run a generate and open a MR/PR with the new script.
This let's you audit the script and make a plausibility check and you'll be notified on changes but have minimal effort to keep the tests running
This is super interesting, is it open source? Would love to talk to you more about how this worked
Hi! Kosta from Octomind here.
We built basically this: Let an LLM agent take a look at your web page and generate the playwright code to test it. Running the test is just running the deterministic playwright code.
Of course, the actual hard work is _maintaining_ end-to-end tests so our agent can do that for you as well.
Feel free to check us out, we have a no-hassle free tier.
Octomind is sick, web agents are such an interesting space; would love to talk to you more about challenges you might've faced in building it
Interesting, 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
How do you get by when every major sites starts blocking headless browsers? A good example right now is Zillow, but I foresee a world where big chunks of the internet are behind captcha and bot detection
That's not really a problem for Stagehand. It's a problem for Selenium, Playwright, Puppeteer and others at the browser automation library level.
it's not really a problem for Playwrite, because Playwrite is really intended to be run by the owners of the website, not as a webscraper.
It may become a real problem for the usefulness of this style of LLM driven browsing.
Right, but I mean it's a plugin issue outside of Stagehand. That's currently how the space treats the issue.
There are plugins that extend the major browser automation libraries to do this sort of thing.
And undetectable browser automation doesn't use Playwright, Puppeteer, or Selenium at all.
It 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.
Appreciate 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
Working with Selenium has always been painful for me so I for one thank you for providing an alternate solution.
That's the same reason everyone else ignores the fact that it's a testing library. Except now you're forcing users to write kludges that wrap around the testing interface.
>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.
Treating UI test code as some kind of static source of truth is the biggest nightmare in all of UI front end development. Web UIs naturally have a ton of "jank" that accumulates over time, which leads to a ton of false negatives; slow API calls, random usages of websockets/SSE, invisible elements, non-idempotent endpoints, etc. etc. And having to write "deterministic" test code for those is the single biggest reason why no one ever actually does it.
I don't care that the page I'm testing has a different DOM structure now, or uses a different button component with a different test ID. All I care about is "can the user still complete X workflow after my changes have been made". If the LLM wants to completely rewrite the underlying test code, I couldn't care less so long as it still achieves that result and is assuring me that my application works as intended E2E.
> Treating UI test code as some kind of static source of truth is the biggest nightmare in all of UI front end development. Web UIs naturally have a ton of "jank" that accumulates over time, which leads to a ton of false negatives; slow API calls, random usages of websockets/SEE, invisible elements, non-idempotent endpoints, etc. etc. And having to write "deterministic" test code for those is the single biggest reason why no one ever actually does it.
It is, in fact, very possible to extract value from testing methods like this, provided you take the proper care and control both the UI and the tests. It's definitely very easy to end up with a flaky suite of tests that's a net drag on productivity, but it's not inevitable.
On the other hand, I have every confidence that an LLM-based test suite would introduce more flakiness and uncertainty than it could rid me of.
>provided you take the proper care and control both the UI and the tests.
And no one ever does. There is zero incentive to spend days wrangling with a flakey UI test throwing a false positive for your new feature, and so the test gets skipped and everyone moves on and forgets about it. I have literally never seen a project where UI tests were continually added to and maintained after the initial build out, simply because it is an immense time sink with no visible or perceived value to product, business, or users, and requires tons of manual maintenance to keep in sync with the application.
This 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.
Thanks 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
My kneejerk reflex: "create-browser-app" is a very generic name, should just have called it "stagehand"
Cool! 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
This is sick! Starred, thanks for sharing :)
I'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?
Thanks so much! Our Stagehand MCP server actually won Anthropic's Claude MCP hackathon :) Check it out: 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
The MCP server is useful, I built a demo of converting bug reports into Playwright tests using it - https://qckfx.com/demo
Whoa -- this is so cool! Is this open source? Would love to check it out
interesting and hope to see this improve with open source GUI Agent vision model projects like OS-Atlas
Hey 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). 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.
I 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.
Yes 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?
Lightpanda does look promising, but this is an important note from the readme: " You should expect most websites to fail or crash."
You'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.
Can it be adapted to use ollama? Seems like a good tool to setup locally as a navigation tool.
Yes, 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/...>
It 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).
We 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
Yeah 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.
Does this open up the possibility of automating an existing open browser tab? (Instead of a headless or specifically opened instance of chrome?)
Have 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.
Afaik no. But if it's access to authenticated resources that you want, you can do so by copying over cookies.
Yes^ 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-contextHave been on the Slack for a while and this crew has had an insane product velocity. Excited to see where it goes!
Thanks so much Zane!!
Does 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?
It'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
Cool 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
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!
Yes! 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
I’m curious how this compares to playwrights already built in codegen:
https://playwright.dev/docs/codegen-intro
Is a chat bot easier to reiterate a test?
Playwright 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
How do you avoid this becoming horrendously expensive per run? Are the results cached if the DOM doesn't change?
The 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.
That 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.
I think a hybrid solution where you use AI if the X path fails or if the test as a whole fails would be ideal. Then cache the results and use them until it fails again.
Definitely a very interesting problem we're trying to dig deep into. We'd welcome any PRs here as well from the community :)
wow. It's like cursor vs vscode movement but for browser automation and scrapping. Kudos to the author. Are there any other similar tools?
Thanks 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
Yea Integuru is pretty cool: https://github.com/Integuru-AI/Integuru
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]
Congratulations. 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.
Thanks so much! Sounds like Stagehand is a perfect fit; would love to hear your thoughts :)
Any attempt on doing something similar but as a browser extension?
That's definitely compelling, but not something we have in mind for the immediate future. Let me know if you end up building something here!
I'm currently working on it :)
See you in two weeks I hope
People 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.
And here I was in trenches with 2 upvotes with Show HN for https://github.com/BandarLabs/clickclickclick
This 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.
This thing that was just released is the future of UI testing? I usually just use the UI to test it.
>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.
The easiest way to programmatically browse the web!!
Thanks so much!! Appreciate the feedback