Anthropic acquires Stainless

Anthropic is at a place where they need the world's best software engineers, and they're willing to comp at insane levels to get them. However: You simply cannot post a Linkedin job for "Really Good Software Engineer, comp $10M+" and make any sense of the inbound applications you'll get. They're not the first to figure this out, and they won't be the last: Successfully building a company, and using that company's products, is actually the best job interview you can ask for if you can pay for that caliber of candidate.

What you should be paying attention to: Stainless is shutting down, and their team is joining Anthropic to build, who knows, some dumb integration to make Hubspot data available in Claude, or something equally as boring. But, Stainless was successful. Be the next Stainless. The idea is already validated, these AI companies have already done this to a handful of companies and they're going to keep doing it.

> As we focus on Claude Platform capabilities and connecting agents to APIs, we’ll be winding down all hosted Stainless products, including our SDK generator. Starting today, new signups, projects, and SDKs will not be available.

For better or worse, it's an acquihire.

Congrats to the team at Stainless, it's a great team to be joining over at Anthropic.

We were an ealy adopter of their Node SDK generator at Mux (and latterly their Typescript and other generators), and the product worked great, and I'm sad to see it be shut down.

At the same time, it's easy to understand why this is a complciated product/market to be in at the moment - it's very tempting and easy to vibe code SDKs from a OpenAPI spec files right now. I would think a lot of teams will just go in that direction (for better or worse), using the same toolchain that the product developers are using today for the product, for effectively no extra cost.

Some clarity about existing users/SDKs would go a long way. Otherwise this reads like "we just bought OpenAI's front door and we're EOLing it. Hopefully no one was planning to use it in the future". Petty and pointless.

I feel like we are seeing agentic coding tools morph into walled gardens with these acquisitions. Anthropic has restricted claude code usage while OpenAI has sort of let Codex fill the void. I am curious to see how this continues to evolve.

Just want to take this moment to say thank you to all the customers I had the opportunity to interact with during my time at Stainless as I expect lots of them are likely to be active in this thread. It has been an honor to work with you all and none of what happened over the past 4 years would have been possible without your trust and support

Stainless blog post: https://www.stainless.com/blog/stainless-is-joining-anthropi...

X: What are you folks doing?

A: Writing docs at an SF AI company for $500k TC.

B: Designing, maintaining, and implementing all features for a platform in the IoT sector in Spain — alone — for €40,000.

A: Spain? I just bought a villa near the beach, close to Alicante. Do you know it?

B: Yes..

As a Stainless customer, this is frustrating!

I get that most of our new customers will use AI to generate client libs. But our existing customer base depends on our Stainless generated client libs. These OpenAPI schema > client lib providers had a bit of lockin since the client libs are all slightly different.

Migration's unfortunately not as easy as just switching to Speakeasy or Openapi generator w/o breaking existing customers.

Here is a powerful OSS extensible alternative from Microsoft. It’s what generates all azure SDKs, docs, CLIs now, and it’s really good.

https://typespec.io/

I worked with Alex (founder of stainless) at Stripe and he's awesome. Happy for him and well deserved. Congrats Alex! :)

Anthropic is getting extremely petty and especially against oai

- ad in superbowl about how they are the good guys.

- dow public PR stunt (they are the ones to give Palantir their model access).

- sues openclaw.

- threatens every use of cc in oss community.

- prevents other companies using claude saying they cant use when they compete.

- never released a single open weight model.

- Dario told OAI is Yolo'ing in compute and they are now doing the same.

- gas lighting developers and then after weeks acknowledging they fiddled with reasoning juice.

- fear mongoring on mythos and then geting compute later and acknowledging publicly once they realized its not significantly better than gpt 5.5 cyber.

- signs a deal with Elon!

- now this!

I'm finding these acquisitions (or acquihire?) are interesting. First Bun, and then Stainless. It's almost like Anthropic wanted to acquire every company that develops foundational technology that they themselves use.

Assuming they bet on Claude getting much better at coding over time, couldn't they themselves cover their own needs with technology that they built themselves?

Is some sort of autonomy over technology they use somehow the goal here?

OpenAI uses stainless for at least some of their SDKs.

Astral, bun, Stainless, Cursor... and more..

Seems like developer tools/tooling are a hot commodity to the current big AI companies?

Incredible and congrats. I'm doing a bit retro that during the boom of AI and LLM, I was busy doing my day job in Java CRUD and figuring things out about micro services.

It had never occurred to me to go like, "I'm going to make an open source product for LLM". How is something like built from scratch from an idea? And what is the idea?

For example, it is fairly straight foreword to build a dash board of something with React as front end + backend API. This will be a typical web app.

But stainless is something different, from my limited knowledge in this space, its appears to be SDK, something like OpenAI SDK that reduces boilerplate code to interact with LLM providers by providing list of tools (MCP), temperature, context memory and bunch of other parameters...

Does anyone have a good guess as to the strategic reasoning behind this?

I know that common reasons for acquisitions are IP, talent, or reducing competition.

It seems like IP can't be the reason here. How is this strategically advantageous to Anthropic?

Congratulations to the Stainless team for their hardwork.

We are offering a 50% off for the first year subscription price at www.apimatic.io for companies impacted by this.

If you're looking for a solid long term SDK and docs partner, APIMatic is the OG CodeGen serving companies like PayPal, Maxio and PayQuicker for the past 10 years.

Reach out to mehdi@apimatic.io and I'll help you migrate.

PS: sorry for the shameless plug but sdks and APIs are my life and blood :-)

Utterly shameless plug, but recently at WorkOS I open sourced our OpenAPI spec to SDK pipeline: https://workos.com/blog/handwritten-sdks-are-dead

We evaluated Stainless & Fern for our 8+ languages but ultimately I couldn’t justify the cost nor ceding control to another organization for something as important as platform DX.

I don't understand why they would buy this company?

Was stainless doing great? Was stainless doing not great? Did they just want to hire some extra skilled engineers? Did they hire them so OpenAI's SDKs are gonna have a setback?

Mmmh

Wait Stainless is not a Rust company???

I had never heard of Stainless, but it is deeply concerning that Anthropic are able to use monopoly money to kill software at their whim. First Bun, and now this. It's one thing for a corporation to do it with their own money, because at some point the board will ask them why they're wasting money. But Anthropic isn't even profitable. They're doing this with billions of dollars of borrowed money. Same thing with OpenAI committing to purchasing an unholy amount of RAM supply and directly causing the 5x price jump, with money they don't have.

I don't understand how investors continue to fund this nonsense. Anthropic wasting money on this should be an overwhelmingly strong signal that the AGI hype is blatant fraud and that software engineers are clearly not being replaced by Anthropic's software if they have to buy more engineers for some tertiary, fifth-order concern so far removed from their main line of business. Yet they just keep getting more and more money dumped on them.

if u can't replace the tools, then acquire the tool makers & shut down the tools.

Interestingly, Anthropic uses Mintlify for their docs. Not Stainless. Obviously, the focus is on SDK generation, but still strange.

I've started to really dislike how anthropic is operating, not very human first or friendly

aside from that, this is literally just an openapi to sdk generator, not like openai can't just generate one

I'm really disappointed that such a great service is getting taken off the market. Happy for their team, but sad for the ecosystem.

This has to be somewhat anti-competitive. Why else sunset the SDK generator service but to hurt any other company (OpenAI, etc) who relies on these for their SDKs?

Anthropic, it would be nice to actually put a link to the website.

OpenAI use(d|s) Stainless too right?

Can't wait for everything to go bum, and finally get to use only what is relevant.

Rust rewrite coming up in a week

What's the best remaining alternative?

Are they buying these for the tech, the people or to prevent supply chain hacks?

Why can't they just partner with these companies? Why do they have to take all these products, open source projects, etc.. and just destroy all that value?

Whats the connection that got them the early in with anthropic?

I am going to assume that anything Anthropic acquires is going to be eventually used against you.

Hopefully Stainless' products will remain available to customers in some form, rather than having them hogged for internal use. Give it time, not all is lost.

Good for them. We built similar tooling at that time, but backed by our own APIs. It's something that has a lot of value, that standardisation needs to exist, but it also makes a lot of sense to fold the team into a company like Anthropic that is so developer centric. Good luck to the team there.

Now if only we had a service that could generate OpenAPI specs automatically...

You can't rely on commercial offerings anymore. They vanish with increasing frequency.

Yet another reason to use open source.

looks like just an excuse to spend capital

Wow

congrats stainless team!

Stainless has 93 people: https://www.linkedin.com/company/stainless-api/people/

It's funny that Anthropic needs to spend millions acquiring a dev doc platform, can't they just vibe code something up with Mythos a few junior devs at Anthropic?

We have Dario claiming SWE development is obsolete and both OpenAI and Anthropic and big tech bros like Musk are still spending millions like this..

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This feels like the Apple playbook, but for software tooling--they are becoming vertically integrated.

Hi

This makes sense, since their business model is built on Steeling everyone's data and feeding it to a monster.