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About Stainless
Industries
Enterprise Software
Company Size
51-200
Company Stage
Series A
Total Funding
$28.5M
Headquarters
New York City, New York
Founded
2022
Overview
StainlessAPI develops tools that help software engineers generate language-idiomatic SDKs from REST APIs. It takes an OpenAPI Specification and automatically produces client libraries tailored to specific programming languages, so developers can use APIs without writing or maintaining multiple language clients. The product works by parsing the API definition and emitting SDKs that follow each language's conventions, enabling fast, consistent integration with APIs. StainlessAPI differentiates itself by focusing on automated SDK generation from OpenAPI, reducing manual boilerplate and ensuring consistency across languages, rather than competing primarily on features like hosting or analytics. Its goal is to speed up API development and maintenance for developers and tech teams, typically via a subscription-based model that scales with enterprise needs.
Simplify's Take
What believers are saying
- $25M Series A from Andreessen Horowitz and Sequoia fuels expansion.
- OpenAI, Anthropic, and Meta drive $1M ARR with hundreds of customers.
- Ruby and Terraform generators now GA, supporting 8 languages including C#.
What critics are saying
- Fern's superior docs and Explorer erode Stainless developer adoption within 6 months.
- Speakeasy's OpenAI SDK customization steals key client OpenAI in 12 months.
- Open-source stainless-tools commoditizes generation, slashing subscriptions in 3 months.
What makes Stainless unique
- Stainless generates idiomatic SDKs from OpenAPI specs using AI-powered compiler.
- stainless.yaml enables precise SDK customization beyond standard OpenAPI.
- GitHub Actions automate SDK updates and release PRs for production repos.
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Funding
Total Funding
$28.5M
Above
Industry Average
Funded Over
2 Rounds
Andreessen HorowitzIndustry standards
Benefits
Health Insurance
Company Equity
Commuter Benefits
Unlimited Paid Time Off
Growth & Insights and Company News
6 month growth
↑ 5%1 year growth
↑ 4%2 year growth
↑ 21%Stainless is excited to announce that the Ruby SDK and Terraform provider generators are now generally available.
Stainless Software Inc. has raised $25M in a Series A funding round led by Andreessen Horowitz, with participation from Sequoia, The General Partnership, and others. The company uses AI to generate SDKs from APIs, supporting languages like Python and Go. Stainless claims hundreds of paying customers, including OpenAI and Meta, and reports $1M in annual recurring revenue. The service offers a free tier and paid plans ranging from $250/month to $30k/year.
Stainless, a startup offering an AI-powered API-to-SDK generator to customers like OpenAI, Anthropic, and Meta, raised a $25M Series A led by a16z (Kyle wiggers/techcrunch).
Rattray, who studied economics at the University of Pennsylvania, has been building things for as long as he can remember, from an underground newspaper in high school to a bike-share program in college. Rattray picked up programming on the side while at UPenn, which led to a job at Stripe as an engineer on the developer platform team. At Stripe, Rattray helped to revamp API documentation and launch the system that powers Stripe's API client SDK.
Besides a focus on generative AI, what do AI startups like OpenAI, Anthropic and Together AI share in common? They use Stainless, a platform created by ex-Stripe staffer Alex Rattray, to generate SDKs for their APIs.Rattray, who studied economics at the University of Pennsylvania, has been building things for as long as he can remember, from an underground newspaper in high school to a bike share program in college. Rattray picked up programming on the side while at UPenn, which led to a job at Stripe as an engineer on the developer platform team.At Stripe, Rattray helped to revamp API documentation and launch the system that powers Stripe’s API client SDK. It’s while working on those projects Rattray observed there wasn’t an easy way for companies, including Stripe, to build SDKs for their APIs at scale.“Handwriting the SDKs couldn’t scale,” he told TechCrunch. “Today, every API designer has to settle a million and one ‘bikeshed’ questions all over again, and painstakingly enforce consistency around these decisions across their API.”Now, you might be wondering, why would a company need an SDK if it offers an API? APIs are simply protocols, enabling software components to communicate with each other and transfer data. SDKs, on the other hand, offer a set of software-crafting tools that plug into APIs. Without an SDK to accompany an API, API users are forced to read API docs and build everything themselves, which isn’t the best experience.Rattray’s solution is Stainless, which takes in an API spec and generates SDKs in a range of programming languages including Python, TypeScript, Kotlin, Go and Java
Stainless is Hiring for 15 Jobs on Simplify!
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About Stainless
Industries
Enterprise Software
Company Size
51-200
Company Stage
Series A
Total Funding
$28.5M
Headquarters
New York City, New York
Founded
2022
Stainless is Hiring for 15 Jobs on Simplify!
Find jobs on Simplify and start your career today