Stainless

Stainless helps you deliver world-class developer interfaces for your API.

AI coding and devtools Developer tools and cloud

Latest funding

$25M Series A · December 10, 2024

Led by Andreessen Horowitz · Source: fundraiseinsider.com

Funding history ↓

Acquired by AAnthropic on May 18, 2026 · Digi Times.

Website: stainless.com.

X: @StainlessAPI · 5,129 followers.

GitHub: stainless-api.

LinkedIn: stainless-api.

Categories: AI coding and devtools Developer tools and cloud.

Stage: Series A.

Based in: New York, United States.

Last round: Dec 10, 2024 · 705 days ago.

On Recent Funding since: Sep 29, 2026.

Signals

X account@StainlessAPI · created Dec 20, 2022 (3 years old) · 5,129 followers

Website registeredMar 30, 1999 (27 years old)

About Stainless

Generate robust and idiomatic SDKs in popular programming languages, token-efficient MCP servers, and SDK-native documentations that evolve with your OpenAPI spec.

TIMELINE · MONEY RAISED

Stainless | 721 days from X account to first raise on record

@StainlessAPI·Raised $25M in 1 sourced round·1 signal before the first raise

Money raised, round by round (amounts linked to their source). Pins are dated signals; hover the icons for dates.

Funding rounds

Date	Round	Amount	Lead	Source
Dec 10, 2024	Series A	$25M	AAndreessen Horowitz	fundraiseinsider.com

Timeline

May 18, 2026
Acquired by AAnthropic
Source: Digi Times
December 20, 2022
X account created
March 30, 1999
Website created

Founders and team

AR
Alex Rattray Founder/CEO

@RattrayAlex · source: stainless.com

Investors

Companies like Stainless

HHumble$51M Series A · Nov 2026
IInflection AISeries B+ · Oct 2025
TTesslSeries A · Jun 2026
SStytch$90M Series B+ · Nov 2021
NNobodyWho$2.35M Pre Seed · Dec 2025
LLinear$82M Series B+ · Jun 2025

Other companies backed by Andreessen Horowitz

GGeneral Translation$27M Series A · Nov 2026
TTutor Intelligence$75M Series B+ · Nov 2026
NNorthwood$375M Series B+ · Nov 2026
LLarridin$30M Series A · Nov 2026
MMidstream Health$20M Series A · Oct 2026
WWabi$55M Series A · Oct 2026

Andreessen Horowitz portfolio →

Sources and API

Every amount links to the page it came from. * Estimated from an accelerator's published standard deal, not a company-specific disclosure. How Recent Funding sources and verifies funding data. The same data as JSON: /api/v1/companies/stainless (get a free API key).