kitio.aiLetta vs Agent Development Kit
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Agent Development Kit 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
- Persistent agent memory
- Agent SDK and API
- Agent Development Environment
- Cloud or self-hosted
- Agent export and import
- Multi-agent composition
- Workflow agents
- Local dev UI
- Built-in evaluation
- Multi-language SDKs
| Feature | Letta | Agent Development Kit |
|---|---|---|
| Best for | Platform for stateful AI agents with long-term memory | Google's open-source toolkit for building and deploying agents |
| Category | Agents & automation | Agents & automation |
| Pricing model | Freemium | Free |
| Starting price | $20/mo | Free |
| Free plan | Yes | Yes, fully free |
| Made by | Letta | |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
Agent Development Kit 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
Letta
- Strong long-term memory design
- Open-source core
- Clear view of agent state
- Developer-focused
- Free plan limited to a few agents
Agent Development Kit
- Backed by Google
- Several programming languages
- Easy path to Google Cloud
- Best experience is on Google Cloud
- Code-first only
Which one should you choose?
Choose Letta if you want:
- Strong long-term memory design
- Open-source core
- Clear view of agent state
Watch out: developer-focused.
Choose Agent Development Kit if you want:
- Backed by Google
- Several programming languages
- Easy path to Google Cloud
Watch out: best experience is on google cloud.
Letta vs Agent Development Kit FAQ
What is the difference between Letta and Agent Development Kit?
Letta: Platform for stateful AI agents with long-term memory. Agent Development Kit: Google's open-source toolkit for building and deploying agents. Both are agents & automation tools.
Is Letta or Agent Development Kit cheaper?
Agent Development Kit is completely free, while Letta is freemium.
Do Letta and Agent Development Kit have free plans?
Letta: Yes. Agent Development Kit: Yes, fully free.
Who makes Letta?
Letta is made by Letta, based in United States.
Who makes Agent Development Kit?
Agent Development Kit is made by Google, based in United States.
Which should I choose, Letta or Agent Development Kit?
Choose Letta if you value strong long-term memory design and open-source core. Choose Agent Development Kit if you value backed by google and several programming languages.