21st Agents SDK vs Character.AI vs Convai vs Flagsmith
| Attribute | ||||
|---|---|---|---|---|
| Category | Developer Tools | AI Agents & Assistants | AI Agents & Assistants | Developer Tools |
| Pricing | Paid | Free tier | Free tier | Free tier |
| Starting price | $6/month | $9.99/month | $5/month | $40/month |
| Free tier | No | Yes | Yes | Yes |
| Free trial | No | No | Yes | No |
| Deployment | — | — | — | Cloud |
| API available | Unknown | Unknown | Unknown | Unknown |
| Platforms | — | — | — | — |
| Certifications | — | — | — | — |
| Integrations | 1 | — | — | — |
| Company | — | Founded 2022 | — | — |
| Feature attributes | ||||
Also consider
Unknown values show as “Unknown”/“—”. Nothing is inferred — see each tool page for sources.