kitio.aiPydantic AI vs Letta
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Pydantic AI 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
- Typed agent outputs
- Function tools
- Multi-provider support
- MCP support
- Logfire tracing
- Persistent agent memory
- Agent SDK and API
- Agent Development Environment
- Cloud or self-hosted
- Agent export and import
| Feature | Pydantic AI | Letta |
|---|---|---|
| Best for | Type-safe Python agent framework from the Pydantic team | 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 | Pydantic | Letta |
| Based in | United Kingdom | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
Pydantic AI 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
Pydantic AI
- Strong typing reduces bugs
- Familiar to Pydantic users
- Model-agnostic
- Code-only
- Fewer prebuilt integrations than LangChain
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 Pydantic AI if you want:
- Strong typing reduces bugs
- Familiar to Pydantic users
- Model-agnostic
Watch out: code-only.
Choose Letta if you want:
- Strong long-term memory design
- Open-source core
- Clear view of agent state
Watch out: developer-focused.
Pydantic AI vs Letta FAQ
What is the difference between Pydantic AI and Letta?
Pydantic AI: Type-safe Python agent framework from the Pydantic team. Letta: Platform for stateful AI agents with long-term memory. Both are agents & automation tools.
Is Pydantic AI or Letta cheaper?
Pydantic AI is completely free, while Letta is freemium.
Do Pydantic AI and Letta have free plans?
Pydantic AI: Yes, fully free. Letta: Yes.
Who makes Pydantic AI?
Pydantic AI is made by Pydantic, based in United Kingdom.
Who makes Letta?
Letta is made by Letta, based in United States.
Which should I choose, Pydantic AI or Letta?
Choose Pydantic AI if you value strong typing reduces bugs and familiar to pydantic users. Choose Letta if you value strong long-term memory design and open-source core.