Bun vs Deno: Head-to-Head Comparison

Quick Verdict

Bun is the better pick for developers wanting speed and built-in tooling. Deno is the better pick for TypeScript-first apps with secure defaults.

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At a Glance

Feature	Bun	Deno
Best For	Developers wanting speed and built-in tooling	TypeScript-first apps with secure defaults
Pricing	Free and open source	Free and open source
Free to Start	Yes	Yes
License	Open source	Open source
Deployment	Runtime	Runtime
Link	Visit Bun	Visit Deno

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Detailed Breakdown

Bun

Fast all-in-one JavaScript runtime and toolkit

Pros:

• Very fast startup
• Built-in bundler, test runner and package manager
• High Node.js compatibility

Cons:

• Some Node.js APIs incomplete
• Younger runtime

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Deno

Secure runtime for JavaScript and TypeScript

Pros:

• Native TypeScript
• Permission-based security
• Built-in tooling and npm support

Cons:

• Smaller ecosystem than Node.js
• Some npm packages are incompatible

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Key Differences

• Positioning: Bun — fast all-in-one JavaScript runtime and toolkit. Deno — secure runtime for JavaScript and TypeScript.
• Both share the same licensing model (open source), so the decision comes down to features and workflow fit.
• Pricing: Bun — free and open source. Deno — free and open source.
• Signature strength: Bun — very fast startup. Deno — native TypeScript.

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Frequently Asked Questions

Is Bun better than Deno?

It depends on your requirements. Bun is a strong fit for developers wanting speed and built-in tooling, while Deno suits TypeScript-first apps with secure defaults.

Is Bun free to use?

Yes, you can start with Bun for free. Pricing model: Free and open source.

Is Deno free to use?

Yes, you can start with Deno for free. Pricing model: Free and open source.

Can I self-host Bun or Deno?

Bun runs inside your own stack: runtime. Deno runs inside your own stack: runtime.

What are the main drawbacks of Bun and Deno?

Bun: some Node.js APIs incomplete; younger runtime. Deno: smaller ecosystem than Node.js; some npm packages are incompatible.