Bun
A unified JavaScript runtime with integrated package management, bundling, and testing
- Vendor
- Anthropic
- Also known as
- bun
What is Bun?
A JavaScript runtime that executes TypeScript natively using JavaScriptCore, bundling a package manager, bundler, and test runner with Node.js compatibility and npm ecosystem support.
Bun pricing
We don't have Bun's full plan breakdown yet (its pricing page resisted automated reading). Here's what we could confirm. Always check live pricing for exact numbers.
What Bun does
The capabilities that matter for package registries, normalised so it lines up with every alternative. “-” means we haven't confirmed it, not that it's missing.
- Role
- Package manager client
- Ecosystem / language
- JavaScript
- Deployment
- CLI-local
- Package formats supported
- Many formats
- Private / scoped packages
- ✓
- Upstream proxy / caching
- ✓
- Lockfile / deterministic installs
- ✓
- Workspaces / monorepo
- ✓
- Content-addressable store
- ✓
- Supply-chain integrity
- ✓
- Vulnerability / licence scanning
- ✓
- Openness
- Open-source
- Pricing model
- Free / OSS
Platform & deployment
Independently observed- CLI
- macOS
- Linux
- Android
- Windows
- Cloud / SaaS
- Self-hosted
Security & compliance
Known vulnerabilities: 2 (0 in the last 12 months), max severity HIGH sourcea count reflects scale & disclosure, not quality
Bun FAQ
Common questions about Bun, answered from independent, dated evidence.
What is Bun?
Bun is a JavaScript runtime and development toolkit designed as a fast alternative to Node.js with built-in package management, testing, and bundling capabilities. It can be adopted incrementally into existing Node.js projects or used as a complete replacement for development tooling. It is indexed under Package Registries.
Source: https://bun.sh
Is Bun free?
Bun offers a free tier, so you can start without paying. Pricing changes often, so verify at source before relying on it.
Source: https://bun.sh
What platforms does Bun support?
Bun supports Windows, macOS, Linux and a command-line interface. Platforms we have not confirmed are simply not listed here rather than ruled out.
Source: https://bun.sh
Can Bun be self-hosted?
Yes. Bun can be deployed self-hosted, so it does not have to run on the vendor's infrastructure.
Source: https://bun.sh
Is Bun open source?
Yes. Bun is published under the MIT licence, a permissive licence that generally allows commercial use and modification. Licence terms can change between releases, so verify against the repository for the version you intend to use.
Bun alternatives
Other package registries we track, ranked by the same independent score.
- pnpmmedium · 65%
- VerdaccioA self-hosted npm registry with package caching and proxying capabilitieshigh · 78%
- RubyGemsThe public repository and package manager for Ruby codelow · 31%
- uvmedium · 62%
- pipPackage installer for Pythonmedium · 68%
- Composer/PackagistA package and dependency manager for PHP projectsmedium · 52%
Compare Bun
Side by side against other package registries, attribute by attribute, with a source on every value.
The vioscaleAI score: one lens on the evidence
Not user reviews and not a paid placement: a confidence-weighted blend of the independent signals below (adoption, activity, security posture, and more), which you can sort and re-weight yourself. Vendors can correct their listing but can never move their rank, and stars are weighted low as a vanity metric. It is one way to read the evidence for Bun, not the verdict.
| Signal | Score | Weight | Contribution | Evidence |
|---|---|---|---|---|
| Package downloads | 82 | 0.15 | 12.1 | ✓ |
| Capabilities | 87 | 0.09 | 7.6 | ✓ |
| Development activity | 63 | 0.11 | 6.8 | ✓ |
| Release cadence | 92 | 0.07 | 6.3 | ✓ |
| Dependent projects | 72 | 0.07 | 4.9 | ✓ |
| Stars | 94 | 0.03 | 2.5 | ✓ |
| Integrations | 0 | 0.05 | 0.0 | - |
| Security posture | 0 | 0.18 | 0.0 | - |
| Security score | 0 | 0.08 | 0.0 | - |
| Developer Q&A activity | 0 | 0.05 | 0.0 | - |
Computed . Re-weight it by intent, or see the full method.
All data & sourcesshow ↓
Every value we hold, with its source, retrieval date, and confidence. This is the evidence behind the score: don't trust it, verify it.
Activity
| Attribute | Value | Evidence |
|---|---|---|
| Commits last 30d | 100 | mediumsource · 2026-09-10 · 65% |
Adoption
Content
| Attribute | Value | Evidence |
|---|---|---|
| Faq | 5 items | mediumsource · 2026-09-10 · 65% |
Features
| Attribute | Value | Evidence |
|---|---|---|
| Capabilities | Role: manager_client · Ecosystem: js · Deployment: cli_local · Workspaces: Yes · Open source: oss · Pricing model: free | mediumsource · 2026-09-14 · 60% |
Language
| Attribute | Value | Evidence |
|---|---|---|
| Primary | Rust | highsource · 2026-09-10 · 90% |
License
| Attribute | Value | Evidence |
|---|---|---|
| Spdx | MIT | highsource · 2026-09-10 · 85% |
Pricing
Release
Security
| Attribute | Value | Evidence |
|---|---|---|
| Vulnerabilities | Count: 2 · Source: https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=npm&package_name=bun&per_page=100 · Last 12m: 0 · Max severity: HIGH | highsource · 2026-09-10 · 90% |
Is Bun the right choice for you?
Tell us the job, the constraints and what you weigh most, and we will rank Bun against the rest of the package registries we index, using the same dated evidence weighted your way.
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