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Letter AI

Open source alternatives to Letter AI

50 open source AI apps to use instead, best rated first.

Top picks

  1. O

    Open WebUI

    Launch

    Self-hosted AI platform that connects local and cloud models, extends with Python, and keeps your data under your control.

    Open sourceSelf-hosted

  2. A

    AutoGPT

    Launch

    Platform for building, deploying, and running AI agents that automate repeatable digital work across research, outreach, content, and support without writing code.

    Open source

  3. P

    pi

    Launch

    Terminal-based coding agent with a minimal core, 15+ LLM providers, tree-structured session history, and a TypeScript extension system for building your own workflows.

    Open source

  4. A

    AFFiNE

    Launch

    An open-source, local-first knowledge base that merges structured docs, infinite whiteboards, databases, and AI into a single workspace for teams and creators.

    Open source

  5. A

    aider

    Launch

    Terminal-based AI coding tool that lets you edit existing codebases or start new projects using LLMs like Claude, GPT, and DeepSeek.

    Open source

  6. A

    AppFlowy

    Launch

    Open source collaborative workspace combining notes, databases, and AI with full data ownership, offline support, and self-hosting options.

    Open source

More AI apps

See all
7
C

Cherry Studio

Desktop AI client for Windows, macOS, and Linux

Launch
8
C

Cline

AI Coding, Open Source and Open Choice

Launch
9
C

Crawl4AI

Open-source web crawler and scraper

Launch
10
E

ego lite

Fastest browser for AI agents

Launch
11
F

FastGPT

FastGPT is a free, open-source platform

Launch
12
J

Jan

Jan runs open-source AI models on your own hardware or connects

Launch
13
K

Keploy

Open source Tool for converting user traffic to Test Cases and Data Stubs

Launch
14
L

Langflow

Build, deploy, and iterate on AI agents, RAG applications, and MCP servers

Launch
15
L

LibreChat

LibreChat is a free and open-source chat interface for assistant AIs

Launch
16
L

LiteLLM

Acts as a unified proxy across 100+ LLMs

Launch
17
L

llama.cpp

C/C++ inference engine for large language models, supporting quantization

Launch
18
L

LobeHub

An open-source AI Agent Workspace

Launch
19
N

NanoClaw

Self-hosted AI agent that connects to WhatsApp, Telegram, Slack

Launch
20
O

Ollama

Load and run large LLMs locally to use in your terminal or build your apps

Launch
21
O

OpenClaw

Open-source personal AI assistant / agent framework

Launch
22
O

OpenCode

Open-source terminal-native AI coding agent

Launch
23
O

OpenHands

AI agent platform that runs autonomous coding agents to plan, write

Launch
24
O

Orca

Agent Development Environment that runs Claude Code, Codex, Gemini

Launch
25
P

Paperclip

Manages teams of AI agents across business functions

Launch
26
P

Phoenix

Arize Phoenix: Open Source AI Development Platform

Launch
27
P

Portkey

Full-stack LLMOps platform to monitor, manage, and improve LLM-based apps

Launch
28
T

Tabby

Self-hosted AI coding assistant that enhances productivity

Launch
29
V

vLLM

Inference and serving engine for large language models, built

Launch
30
W

Warp

Terminal built for running AI coding agents like Claude Code, Codex

Launch
31
Z

Zed

Your last next editor

Launch
32
U

Unsloth

Local UI to run and train LLMs and diffusion models

Launch
33
T

Theia IDE

An extensible open-source IDE

Launch
34
P

PhotoPrism

AI-Powered Photos App

Launch
35
E

ECC

The agent harness performance optimization system

Launch
36
G

Graphify

Turn any codebase, with its docs, SQL schemas, configs, and PDFs

Launch
37
C

Codex

Lightweight coding agent that runs in your terminal

Launch
38
U

Upscayl

Free and Open Source AI Image Upscaler

Launch
39
C

Chatbox AI

Chatbox AI enables chat with documents, images

Launch
40
F

Folo

Folo is the AI RSS Reader

Launch
41
N

Netron

Visualizer for neural network and machine learning models

Launch
42
G

Gorilla

Training and Evaluating LLMs for Function Calls (Tool Calls)

Launch
43
S

Strix

Open-source AI penetration testing tool to find

Launch
44
C

CC Switch

A cross-platform desktop All-in-One assistant for Claude Code, Codex, OpenCode

Launch
45
1

1Panel

Comprehensive web-based tool for Linux server administration

Launch
46
A

Agno

Open-source platform that enables developers to create

Launch
47
A

AnythingLLM

A desktop and self-hostable AI app for chatting

Launch
48
B

Buzz

Workspace that combines team chat, project planning, and git management

Launch
49
C

Chat2DB

DBMS 、BI 、Report 、 NL2SQL、NL2Report

Launch
50
C

Chroma

Open-source vector database designed for AI applications

Launch

About Letter AI

L

Letter AI

End-to-end content, learning, & deal intelligence for B2B sales teams

Letter AI is the world's first generative AI powered revenue enablement platform. Build and maintain all the collateral and training you need 10x faster with generative AI. Personalize instantly by vertical or individual customers using existing data. Ask questions in real-time to your own co-pilot with expertise in your data.

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Made by
Letter AI
Category
AI
Website
letter.ai