AssemblyAI vs Not Diamond
Which Developer Tools AI tool is better in 2026?
AssemblyAI
AI models for accurate speech recognition
Not Diamond
Data-driven recommendation and routing layer that sends each prompt to the best AI model
Side-by-side
AssemblyAI leads on both fronts — more capital raised ($78M) and a lower entry price than Not Diamond.
| Metric | AssemblyAI | Not Diamond |
|---|---|---|
| Taglinei | AI models for accurate speech recognition | Data-driven recommendation and routing layer that sends each prompt to the best AI model |
| Foundedi | 2017🏆 | — |
| HQi | San Francisco, US | San Francisco, United States |
| Employeesi | 100-200🏆 | — |
| Neuron scorei | 48 | 64🏆 |
| Total fundingi | $78M🏆 | $2.3M |
| Latest roundi | Series B · Sep 2022 | Pre-Seed · Jul 2024 |
| Valuationi | $500M🏆 | — |
| Cheapest paid plani | Pricing not disclosed🏆 | Pricing not disclosed |
| Free plani | ✓ | ✓ |
| Free triali | ✗ | ✓ |
| Top tier pricei | Pricing not disclosed | Pricing not disclosed |
| Pricing summaryi | Free | Free |
| Categoriesi |
Capability matrix
Developer-facing capabilities and access signals for AssemblyAI and Not Diamond.
| Capability | AssemblyAI | Not Diamond |
|---|---|---|
| MCP support | ✗ | ✗ |
| Public API | ✓ | ✓ |
| Webhooks | ✗ | ✗ |
| OAuth 2.0 | ✗ | ✗ |
| SDK languages | 7 (Python, TypeScript, JavaScript, Go…) | — |
| Free plan | ✓ | ✓ |
| Free trial | ✗ | ✓ |
| Verified | ✓ | ✗ |
| Active deal | ✗ | ✗ |
🟢 Strengths of AssemblyAI
- Has raised more capital ($78M vs $2.3M)
- Newer company (2017)
- Verified profile
🔵 Strengths of Not Diamond
- Higher Neuron score (64 vs 48)
- Offers a free trial
Which should you choose?
Choose AssemblyAI if price matters most — it starts at Free, which is friendlier for teams watching burn. Both AI Developer Tools tools ship core features, so the cost delta often decides it for small teams and solo operators.
Choose AssemblyAI if you want the most established option — it has raised $78M, 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
AssemblyAI vs Not Diamond — which is better?
It depends on your priority. AssemblyAI has raised more capital and is the more established option; Not Diamond has broader feature depth. See the side-by-side table above.
Is AssemblyAI cheaper than Not Diamond?
Yes — AssemblyAI's cheapest paid plan is Free, while Not Diamond's is Free.
Do AssemblyAI and Not Diamond offer free plans?
AssemblyAI: Yes, has a free plan. Not Diamond: Yes, has a free plan.
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