Cossistant is an open-source, AI-native customer support platform for React and Next.js developers and SaaS startups that need a customizable chat support widget with AI support agents, real-time messaging, and complete backend infrastructure they can host themselves.

What it is

Cossistant is an open-source chat support widget for the React ecosystem, built by developers for developers who need a flexible, customizable chat solution that integrates into their own applications. It ships headless components, real-time messaging, and complete backend infrastructure under a code-first, API-driven philosophy, with documentation written to be AI-friendly. The project is distributed as a TypeScript monorepo managed with Turborepo and Bun, and it is published to npm as two packages: @cossistant/react, a React SDK with headless hooks and primitives, and @cossistant/next, which provides Next.js-specific bindings and utilities. The GitHub description frames it as an open-source customer support platform with fully customizable AI support agents for developers and startups shipping SaaS.

The concrete problem it solves is the gap between a hosted, closed chat widget and the amount of control a SaaS team actually wants over support. Instead of embedding a third-party widget whose UI, data flow, and agent behaviour cannot be changed, developers get headless primitives they compose into their own interface, plus a backend they can run themselves. That backend is assembled from named, replaceable pieces: a Hono API layer, tRPC for typed client-server calls, Drizzle ORM, Better Auth for authentication, WebSockets for live messaging, and Docker-based Postgres and Redis for persistence and real-time state. The result is a support stack that covers the widget, the agent logic, and the server side rather than only one of those layers.

Key capabilities

• @cossistant/react provides headless hooks and primitives, so the chat UI is composed from application components rather than a fixed widget shell.
• @cossistant/next adds Next.js-specific bindings and utilities for teams building on that framework.
• Real-time messaging is delivered over WebSockets alongside the API layer.
• Backend infrastructure ships as part of the project: a Hono API, tRPC procedures, Drizzle ORM for data access, and Better Auth for authentication.
• The documented stack runs on Docker with Postgres and Redis, covering both relational storage and the real-time layer.
• Fully customizable AI support agents are supported, matching the repository topics agent, ai, and aiagent.
• Documentation includes a Quickstart Guide for application developers and a Contributors Guide for people working on the project itself, with a Discord community alongside GitHub Issues.

Who uses it and how

• React and Next.js SaaS teams embed the widget through @cossistant/react or @cossistant/next and control its presentation with their own components.
• Startups shipping SaaS use customizable AI support agents to handle customer conversations while keeping the conversation data inside infrastructure they operate.
• Self-hosting teams run the stack with Docker, which requires operating Postgres and Redis instances in addition to the Node-based API process.
• Contributors work against the Turborepo monorepo, following the Contributors Guide and coordinating through GitHub Issues and Discord.
• The project participates in the Vercel open source program and invites other open source projects to join its own open source program.

Getting started

Install the SDK from npm as @cossistant/react or @cossistant/next, then follow the Quickstart Guide at cossistant.com/docs/quickstart. A hosted option is available at cossistant.com, while self-hosting uses the repository's Docker setup for Postgres and Redis.

How it compares

The facts provided name no paid products that Cossistant replaces, and no directly comparable tools are listed either. Within this registry it stands alone in its category description, so any comparison to other chat or support products would have to come from outside the material available here.

When to use it — and when not to

A self-hoster must operate the full backend: Postgres and Redis via Docker, the Hono API process, and Better Auth, so this is not a drop-in service with nothing to run. The licensing is the sharpest constraint, since AGPL-3.0 applies to non-commercial use only and commercial use or deployments requiring a setup fee need a separate commercial licence arranged by contacting the maintainers. Teams that want a permissive licence without a commercial conversation, or that have no appetite for running database and cache infrastructure, should look elsewhere despite the otherwise low issue count of four open issues.