Celestial AI vs RadixArk
Which Infrastructure AI tool is better in 2026?
Celestial AI
Photonic Fabric optical interconnect for AI infrastructure
RadixArk
Open infrastructure for frontier AI, built on SGLang
Side-by-side
Celestial AI is the more established option (raised $515M); pricing is comparable on both sides.
| Metric | Celestial AI | RadixArk |
|---|---|---|
| Taglinei | Photonic Fabric optical interconnect for AI infrastructure | Open infrastructure for frontier AI, built on SGLang |
| Foundedi | 2020🏆 | 2025 |
| HQi | Santa Clara, United States | San Francisco, US |
| Employeesi | — | 1-10🏆 |
| Neuron scorei | 77🏆 | 56 |
| Total fundingi | $515M🏆 | $100M |
| Latest roundi | Series C1 · Mar 2025 | Seed · May 2026 |
| Valuationi | — | $400M🏆 |
| Cheapest paid plani | Pricing not disclosed | Pricing not disclosed |
| Free plani | ✗ | ✓ |
| Free triali | ✗ | ✗ |
| Top tier pricei | Pricing not disclosed | Pricing not disclosed |
| Pricing summaryi | Custom | Open source |
| Categoriesi |
Capability matrix
Developer-facing capabilities and access signals for Celestial AI and RadixArk.
| Capability | Celestial AI | RadixArk |
|---|---|---|
| MCP support | ✗ | ✗ |
| Public API | ✗ | ✓ |
| Webhooks | ✗ | ✗ |
| OAuth 2.0 | ✗ | ✗ |
| SDK languages | — | — |
| Free plan | ✗ | ✓ |
| Free trial | ✗ | ✗ |
| Verified | ✗ | ✗ |
| Active deal | ✗ | ✗ |
🟢 Strengths of Celestial AI
- Has raised more capital ($515M vs $100M)
- Higher Neuron score (77 vs 56)
- More mature (2020)
🔵 Strengths of RadixArk
- Offers a free plan
- Newer company (2025)
Which should you choose?
Choose RadixArk if price matters most — it starts at Open source, which is friendlier for teams watching burn. Both AI Infrastructure tools ship core features, so the cost delta often decides it for small teams and solo operators.
Choose Celestial AI if you want the most established option — it has raised $515M, 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
Celestial AI vs RadixArk — which is better?
It depends on your priority. Celestial AI has raised more capital and is the more established option; RadixArk has broader feature depth. See the side-by-side table above.
Is Celestial AI cheaper than RadixArk?
No — RadixArk's cheapest paid plan is Open source, while Celestial AI's is Custom.
Do Celestial AI and RadixArk offer free plans?
Celestial AI: Paid only. RadixArk: Yes, has a free plan.
Explore more AI Infrastructure tools
Contextual paths to related AI startups, deals and rankings.