The deciding difference is operational: Letta can run on infrastructure you control, OpenAI Agents SDK cannot. If that constraint is real for you, it settles the choice before anything else is considered.
Lightweight loop with handoffs, guardrails and sessions.
Stateful agent server where memory is the primary abstraction.
| OpenAI Agents SDK | Letta | |
|---|---|---|
| Licence | Open source | Open source |
| Pricing | usage based | freemium |
| Self-hostable | No | Yes |
| Languages | Python, TypeScript | Python, TypeScript |
| Install | pip install openai-agents | pip install letta |
| Keys required | OPENAI_API_KEY | None |
The deciding difference is operational: Letta can run on infrastructure you control, OpenAI Agents SDK cannot. If that constraint is real for you, it settles the choice before anything else is considered. OpenAI Agents SDK: Lightweight loop with handoffs, guardrails and sessions. Letta: Stateful agent server where memory is the primary abstraction.
OpenAI Agents SDK is a hosted service only. Letta can run on your own infrastructure.
OpenAI Agents SDK is open source (usage based). Letta is open source (freemium).
Every page here answers to Accept: text/markdown and returns the same content at roughly a tenth the tokens. No separate site, no toggle — same URL.
curl -s -H "Accept: text/markdown" https://newagent.build/compare/openai-agents-sdk-vs-letta