Bun
AcquiredA fast all-in-one JavaScript runtime
San Francisco, United States · Founded 2019 · $7.0M raised
- Headquarters
- San Francisco, California
- Employees
- 11–50
- Founded
- 2019
- Business Model
- b2d
- Website
- bun.sh
- Total Funding
- $7.0M
- Last Round
- $7.0M SeedAug 2022
- Rounds
- 1
- Acquired by
- AnthropicDec 2025
Totals include recorded grants and other qualifying funding, not just equity. What counts toward funding.
About
Founded in 2019 by Jarred Sumner in San Francisco, Bun is a fast, incrementally adoptable all-in-one JavaScript, TypeScript, and JSX toolkit. Built on top of JavaScriptCore (Safari's JS engine), Bun starts 3x faster than Node.js and provides an integrated package manager (up to 30x faster than npm), test runner (Jest-compatible), and bundler. It aims for 100% Node.js compatibility and includes built-in APIs for HTTP servers, WebSockets, PostgreSQL/MySQL/SQLite, Redis, S3, file I/O, and more. Bun was incubated through Y Combinator and had 13 employees as of its YC profile. In 2025, Bun joined Anthropic.
Summary
Bun is a Developer Tools company based in San Francisco, United States, founded in 2019. It has raised $7.0M in total across 1 round, most recently a $7.0M Seed round in Aug 2022. Investors include Anthropic, Kleiner Perkins and Y Combinator.
Tech & App Stack
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Funding & Exit History
Dec 2025
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Funding: Seed. Amounts, valuations, and investors where available.
Investors
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