kitio.aiOpenAI Agents SDK vs Letta
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. OpenAI Agents SDK is completely free, while Letta is freemium.
At a glance
Best for
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Agent handoffs
- Function and hosted tools
- Guardrails
- Sessions
- Built-in tracing
- Persistent agent memory
- Agent SDK and API
- Agent Development Environment
- Cloud or self-hosted
- Agent export and import
| Feature | OpenAI Agents SDK | Letta |
|---|---|---|
| Best for | OpenAI's lightweight framework for multi-agent workflows | Platform for stateful AI agents with long-term memory |
| Category | Agents & automation | Agents & automation |
| Pricing model | Free | Freemium |
| Starting price | Free | $20/mo |
| Free plan | Yes, fully free | Yes |
| Made by | OpenAI | Letta |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
OpenAI Agents SDK is completely free, while Letta is freemium.
Free plan
Cheapest paid plan
Top plan
Free trial
5 plans
Free
Free
- Limited stateful agents
- 5 MiB storage per memory repo
- Bring your own API keys
Pro
$20/mo
- Up to 20 stateful agents
- Letta Auto weekly + monthly quota
- 50 MiB storage per memory repo
Teams Pro
$20/mo
- Per seat
- Share agents with access control
- All Pro features
API Plan
$0.10 / active agent / mo
- Unlimited agents
- $0.00015 per sec tool execution
- Pay-as-you-go LLM usage
Enterprise
Contact sales
- Role-based access control
- SAML/OIDC SSO
- Dedicated support
Prices in USD, checked Oct 28, 2026 or later. Plans change often, so confirm on each tool's site before you buy.
Pros and cons
OpenAI Agents SDK
- Small, easy-to-learn API
- Good tracing
- Official OpenAI support
- Model usage billed separately
- Fewer integrations than larger frameworks
Letta
- Strong long-term memory design
- Open-source core
- Clear view of agent state
- Developer-focused
- Free plan limited to a few agents
Which one should you choose?
Choose OpenAI Agents SDK if you want:
- Small, easy-to-learn API
- Good tracing
- Official OpenAI support
Watch out: model usage billed separately.
Choose Letta if you want:
- Strong long-term memory design
- Open-source core
- Clear view of agent state
Watch out: developer-focused.
OpenAI Agents SDK vs Letta FAQ
What is the difference between OpenAI Agents SDK and Letta?
OpenAI Agents SDK: OpenAI's lightweight framework for multi-agent workflows. Letta: Platform for stateful AI agents with long-term memory. Both are agents & automation tools.
Is OpenAI Agents SDK or Letta cheaper?
OpenAI Agents SDK is completely free, while Letta is freemium.
Do OpenAI Agents SDK and Letta have free plans?
OpenAI Agents SDK: Yes, fully free. Letta: Yes.
Who makes OpenAI Agents SDK?
OpenAI Agents SDK is made by OpenAI, based in United States.
Who makes Letta?
Letta is made by Letta, based in United States.
Which should I choose, OpenAI Agents SDK or Letta?
Choose OpenAI Agents SDK if you value small, easy-to-learn api and good tracing. Choose Letta if you value strong long-term memory design and open-source core.