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Alternatives to Letta

Letta is an agent framework by Letta: Open-source agent harness for stateful agents whose memory persists and improves with use, with a terminal UI, app server and TypeScript SDK. If it doesn't fit your setup, these 12 agent frameworks cover similar ground. They are ordered by how closely they match Letta and by our rank, which weighs adoption, freshness and documentation; money never changes the order. Pi Agent Core leads the list (more GitHub stars (117.6K)). Each entry shows data reasons to switch, and you can open a side-by-side comparison with Letta.

Updated Oct 26, 2026 · Built from catalog data; how we rank and grade

You're replacing

Letta

Open-source agent harness for stateful agents whose memory persists and improves with use, with a terminal UI, app server and TypeScript SDK.

12 alternatives

Ordered by how closely each matches Letta (shared product, category or stated alternative) and by rank.

  1. 1
    Pi Agent Core

    Earendil

    Minimal TypeScript agent harness with an agent runtime, multi-provider LLM API, terminal UI and coding agent CLI that users extend themselves.

    • More GitHub stars (117.6K)

    ★ 117.6K↓ 5.1M/wkLast active Oct 24, 2026Compare →

  2. 2
    CopilotKit

    CopilotKit

    Open-source SDK that connects AI agents to app front ends with chat UI, generative UI, shared state and human approvals; creator of the AG-UI protocol.

    • 38.2K GitHub stars
    • Active in the last 30 days

    ★ 38.2K↓ 286.2K/wkLast active Oct 24, 2026Compare →

  3. 3
    Deep Agents

    LangChain

    Opinionated agent harness on LangGraph with sub-agents, filesystem access, context management, persistent memory and approval of tool calls.

    • Supports Python

    ★ 30.6K↓ 1.9M/wkLast active Oct 24, 2026Compare →

  4. 4
    Mastra

    Mastra

    TypeScript framework for AI agents and apps with graph-based workflows, memory, suspend-and-resume approvals, MCP servers and model routing.

    • 29.1K GitHub stars
    • Active in the last 30 days

    ★ 29.1K↓ 1.4M/wkLast active Oct 24, 2026Compare →

  5. 5
    Vercel AI SDK

    Vercel

    TypeScript toolkit for AI apps and agents with a unified provider API, streaming, UI hooks and a wrapper for running established agent harnesses.

    • 27.5K GitHub stars
    • Active in the last 30 days

    ★ 27.5KLast active Oct 23, 2026

  6. 6
    Strands Agents

    AWS

    Open-source Python and TypeScript SDK for model-driven agents, with tools, MCP, multi-agent patterns and streaming.

    • Supports Python

    ★ 8.9K↓ 8.9M/wkLast active Oct 24, 2026

  7. 7
    GitHub Copilot SDK

    GitHub

    Multi-language SDKs for embedding the GitHub Copilot agent runtime, with planning, tool calls and file edits, in your apps.

    • Supports Python and Go

    ★ 10.6K↓ 1.2M/wkLast active Oct 24, 2026

  8. 8
    Genkit

    Google

    Open-source Firebase framework for AI features and agent workflows in JavaScript, Go, Python and Dart, with model plugins.

    • Supports JavaScript and Go

    ★ 6.5K↓ 95.8K/wkLast active Oct 23, 2026

  9. 9
    trueforge

    truefoundry

    Open-source agent harness that runs the model loop for you, with MCP tools, skills, sandboxing, approvals and a chat UI.

    • 6.4K GitHub stars
    • Active in the last 30 days

    ★ 6.4KLast active Oct 24, 2026

  10. 10
    LlamaIndex

    LlamaIndex

    Open-source Python toolkit for RAG and agents over your own data, with event-driven workflows and 300+ integration packages.

    • More GitHub stars (52.6K)
    • Supports Python

    ★ 52.6K↓ 1.4M/wkLast active Oct 14, 2026

  11. 11
    ADK for TypeScript

    Google

    TypeScript toolkit for agents with Zod-typed tools, graph and multi-agent workflows, and Node.js or browser runtimes.

    • 1.4K GitHub stars
    • Active in the last 30 days

    ★ 1.4K↓ 143.5K/wkLast active Oct 23, 2026

  12. 12
    VoltAgent

    VoltAgent

    TypeScript framework for AI agents with tools, memory, RAG, MCP and sub-agents, paired with a Cloud or self-hosted console.

    • 10.9K GitHub stars
    • Active in the last 30 days

    ★ 10.9KLast active Sep 28, 2026

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