// the find
openimsdk/open-im-server
IM Chat OpenClaw
OpenIM Server is the backend for OpenIM, a Go instant messaging system built to be embedded in other products rather than installed as a chat app. It runs a WebSocket gateway, RPC services for users, groups, friends and messages, and a transfer pipeline on Kafka, backed by MongoDB, Redis and MinIO. It suits teams that want to self-host the messaging backend for their own app and are willing to run a fairly heavy stack to do it.
The gateway is split from the RPC services and the message transfer workers. Each runs as its own binary under cmd/ with its own YAML in config/, so the WebSocket tier can scale apart from the storage-facing code. Webhooks fire before and after events such as sends and group changes, which is where a business system usually plugs its own rules into chat, and it is built into the core rather than added on. Offline push sits behind one interface in internal/push/offlinepush, with FCM, Getui and JPush implementations, so changing providers does not touch the message path. The license is Apache-2.0, and the repo ships Docker Compose files, build scripts and a full set of Kubernetes manifests.
A working deployment is about a dozen service binaries plus Kafka, MongoDB, Redis, MinIO and a service discovery layer. For a small team, running the infrastructure will take longer than building the chat feature. The README claims support for groups of hundreds of thousands, millions of users and billions of messages, but gives no benchmark, hardware or test setup behind it, so treat that as a claim until you have run your own load test. Most of the substance lives outside the README: the architecture and configuration reference is on docs.openim.io and in diagrams, so you will end up reading source to answer some questions. It is also the server half of a pair. Most client behaviour lives in openim-sdk-core, so adopting the server means adopting its protocol and SDK together.