Letta vs 
Google ADK
Letta vs Google ADK compared for 2026 — features, license, ease of use, performance and which one to choose. Stateful agents with long-term memory vs Google's official Agent Development Kit.
Updated regularly · curated by OpenSourceAI.tech
Letta vs Google ADK at a glance
| Spec | Letta | Google ADK |
|---|---|---|
| Category | AI agent framework | AI agent framework |
| Type | Agent runtime (memory) | Agent framework |
| License | Apache-2.0 | Apache-2.0 |
| Runs locally | Self-hosted | Partial |
| Primary language | Python | Python |
| Ease of use | Advanced | Intermediate |
| Best for | agents that remember across sessions | production agents on the Google/Gemini stack |
| GitHub stars | 23.8k | 20.6k |
How Letta and Google ADK score
| Criterion | Letta | Google ADK |
|---|---|---|
| Popularity | 3.5 | 3.5 |
| Maintenance | 5.0 | 5.0 |
| Ease of use | 2.5 | 3.5 |
| Privacy | 4.5 | 3.5 |
| License freedom | 5.0 | 5.0 |
Scores are computed automatically from public signals — GitHub stars (popularity), recent commit activity (maintenance), license type (freedom), local-first design (privacy) and onboarding complexity (ease of use). Indicative, not a verdict.
What each one is
Letta
Letta (formerly MemGPT) is a framework and server for building stateful agents with long-term memory that persists across sessions, with a visual agent editor.
- Persistent long-term agent memory
- Server with REST API and visual editor
- Model-agnostic and self-hostable
Google ADK
ADK is Google's code-first framework for building, evaluating and deploying agents: hierarchical multi-agent systems, workflow control, built-in eval and a path to Vertex AI.
- Model-agnostic but optimized for Gemini
- Workflow agents give deterministic orchestration
- Built-in evaluation and deployment story
Key differences
Letta is agent runtime (memory), while Google ADK is agent framework. Letta leans more advanced-friendly, whereas Google ADK is more suited to intermediate users. They also differ in how they run (Self-hosted vs Partial). In short, Letta fits agents that remember across sessions, and Google ADK fits production agents on the Google/Gemini stack.
Which should you choose?
Choose Letta for agents that remember across sessions. Choose Google ADK for production agents on the Google/Gemini stack.
There is rarely one winner — many setups use both. The right pick depends on your hardware, your team's skills, and whether you value simplicity or control.
Frequently asked questions
Is Letta or Google ADK easier to use?
Google ADK is generally the easier of the two to get started with, while Letta rewards more setup with more control.
Are Letta and Google ADK free?
Letta is free and open source (Apache-2.0), and Google ADK is free and open source (Apache-2.0). Neither charges for the core software.
Can I run Letta and Google ADK locally?
Letta: self-hosted · Google ADK: partial. Both can be used without sending your data to a third-party cloud where their setup allows.
Letta vs Google ADK — which should I pick in 2026?
Choose Letta for agents that remember across sessions. Choose Google ADK for production agents on the Google/Gemini stack.
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