# CrudWS

> CrudWS is an open protocol for real-time CRUD over WebSockets: create, read, update and delete records over one connection, with instant push to every subscriber.

CrudWS (crud.ws) is an open, language-agnostic protocol for real-time CRUD over WebSockets, developed by MARCODES GmbH (Grünwald, Germany). It is in development: the specification is a draft (v0) and there is an Early Access waitlist. There is no public release, SDK or hosted service yet.

## Facts

- Status: In development · Early Access
- Type: Open protocol for real-time CRUD over WebSockets (JSON text frames, subprotocol crudws.v0)
- Works with: any language or framework that can open a WebSocket and parse JSON
- Publisher: MARCODES GmbH
- Address: Lena-Christ-Str. 2, 82031 Grünwald
- Managing director: Marco Hochmuth
- E-mail: hi@marcodes.com
- Company website: https://www.marcodes.com

## Protocol teaser (draft v0, subject to change)

JSON text frames over WebSocket. Every frame has an op. Requests carry a ref that the server echoes in its answer, so answers may arrive in any order.

- `hello` (client to server): Open the session: protocol version and credentials
- `subscribe` (client to server): Receive changes for a resource, optionally filtered
- `unsubscribe` (client to server): Stop a subscription
- `create` (client to server): Insert a record
- `read` (client to server): Fetch one record by id or a filtered list
- `update` (client to server): Change fields, with the version the client last saw
- `delete` (client to server): Remove a record, with its version
- `ping` (client to server): Keep the connection alive
- `welcome` (server to client): Session accepted: id, heartbeat, granted permissions
- `snapshot` (server to client): Current records and a cursor, answer to subscribe or read
- `ack` (server to client): Write accepted, with the new version
- `change` (server to client): Pushed to subscribers: created, updated or deleted
- `conflict` (server to client): Write rejected: stale version, current record attached
- `error` (server to client): Request failed: code and message
- `pong` (server to client): Answer to ping

## Pages

- [CrudWS · Real-time CRUD over WebSockets, an open protocol](https://www.crud.ws/): CrudWS is an open protocol for real-time CRUD over WebSockets: create, read, update and delete over one connection, with instant push and versioned writes.

## Optional

- [Full content of all pages](https://www.crud.ws/llms-full.txt)