21st vs Builder.io
Which Design AI tool is better in 2026?
21st
Infrastructure and UI building blocks for the agentic internet
Builder.io
Visual AI platform: design-to-code, AI app building and an agentic CMS
Side-by-side
Builder.io is the more established option (raised $62M); pricing is comparable on both sides.
| Metric | 21st | Builder.io |
|---|---|---|
| Taglinei | Infrastructure and UI building blocks for the agentic internet | Visual AI platform: design-to-code, AI app building and an agentic CMS |
| Foundedi | 2026 | 2018🏆 |
| HQi | San Francisco, US | San Francisco, United States |
| Employeesi | 1-10🏆 | — |
| Neuron scorei | 50 | 72🏆 |
| Total fundingi | $500K | $62M🏆 |
| Latest roundi | Seed · Jan 2026 | Series B |
| Valuationi | — | — |
| Cheapest paid plani | Pricing not disclosed | Pricing not disclosed |
| Free plani | ✗ | ✓ |
| Free triali | ✗ | ✓ |
| Top tier pricei | Pricing not disclosed | Pricing not disclosed |
| Pricing summaryi | Pricing not listed | Free |
| Categoriesi |
Capability matrix
Developer-facing capabilities and access signals for 21st and Builder.io.
| Capability | 21st | Builder.io |
|---|---|---|
| MCP support | ✗ | ✓ |
| Public API | ✗ | ✓ |
| Webhooks | ✗ | ✓ |
| OAuth 2.0 | ✗ | ✓ |
| SDK languages | — | 5 (JavaScript/TypeScript, React, Vue, Angular…) |
| Free plan | ✗ | ✓ |
| Free trial | ✗ | ✓ |
| Verified | ✗ | ✗ |
| Active deal | ✗ | ✗ |
🟢 Strengths of 21st
- Newer company (2026)
🔵 Strengths of Builder.io
- Has raised more capital ($62M vs $500K)
- Higher Neuron score (72 vs 50)
- Offers a free plan
- Offers a free trial
Which should you choose?
Choose Builder.io if price matters most — it starts at Free, which is friendlier for teams watching burn. Both AI Design tools ship core features, so the cost delta often decides it for small teams and solo operators.
Choose Builder.io if you want the most established option — it has raised $62M, suggesting more runway for enterprise features, support, and long-term roadmap. For mission-critical workflows or larger teams, that stability often outweighs a lower monthly price.
Frequently asked questions
21st vs Builder.io — which is better?
It depends on your priority. 21st is the leaner option; Builder.io has broader feature depth. See the side-by-side table above.
Is 21st cheaper than Builder.io?
No — Builder.io's cheapest paid plan is Free, while 21st's is Pricing not listed.
Do 21st and Builder.io offer free plans?
21st: Paid only. Builder.io: Yes, has a free plan.
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