Bun vs Fastify
Bun vs Fastify, compared side by side on 12 data points: what each one does, how big it is, what it has raised, the tech running each site, and what users report. We score both out of 100 on traction, team and visibility: Bun is on 59/100 and Fastify on 12/100.
Where each one leads
Bun
- our overall score: 59/100 against 12/100
- agent readiness: 43/100 against 36/100
Fastify
Leads on none of the measures we hold for both companies.
At a glance
| Measure | Bun | Fastify |
|---|---|---|
| What it is | A fast, all-in-one JavaScript toolkit including a runtime, bundler, test runner, and package manager. | An open-source, highly efficient web framework for Node.js focused on speed and low overhead. |
| Category | Developer Tools, JavaScript Runtime, Bundler, Transpiler | Developer Tools, Open Source, API Platform, Serverless |
| Sells toBusiness model | B2B | B2B |
| Offering | Software | Software |
| Founded | 2021 | Not published |
| Headquarters | San Francisco, United States | Not published |
| Status | Active | Active |
Size, funding and growth
| Measure | Bun | Fastify |
|---|---|---|
| Total funding | $7.0M | Not published |
StartupHub scores
Our own 0-100 ratings. They measure company strength and site quality, not which product suits you.
| Measure | Bun | Fastify |
|---|---|---|
| StartupHub scoreOur 0-100 rating | 59/100 | 12/100 |
| Team | Not published | 30/100 |
| Agent readinessHow well an AI agent can read and act on the site | D (43/100) | F (36/100) |
| Domain ratingLink authority, 0-100 | 83/100 | 76/100 |
Technology
Detected on each public site, so it reflects the marketing stack as well as the product.
| Measure | Bun | Fastify |
|---|---|---|
| Hosting | Vercel | Not detected |
| CDN | Cloudflare | Fastly |
| Frameworks | Tailwind CSS | Tailwind CSS |
| Analytics | Plausible | Not detected |
| Open source | Yes | No |
| Self-hostable | Yes | No |
Bun vs Fastify: common questions
Which is better, Bun or Fastify?
On our 0-100 score Bun rates higher (59/100 against 12/100). The score weights traction, team, visibility and profile completeness, so it reflects company strength rather than which product suits you. We compare the two on 12 data points above: read the rows that match what you are buying for.
How do Bun and Fastify compare on the numbers?
Bun leads on our overall score (59/100 against 12/100), agent readiness (43/100 against 36/100).
Read the full Bun review and pricing or the Fastify review and pricing. You can also browse other Bun alternatives we track.