> ## Documentation Index > Fetch the complete documentation index at: https://docs.arcus.xyz/llms.txt > Use this file to discover all available pages before exploring further. # User fills > > **Endpoint:** `wss://api.testnet.arcus.xyz/v1/ws` — one socket multiplexes every channel and RPC request. Click **Connect**, then send the example subscribe message below to start receiving data. Per-user fill stream. Snapshot on subscribe contains recent fills; streaming updates deliver each new fill as orders are matched. Snapshot is sent once on connect only. `LIQUIDATION` and `ADL` fills also appear here (taker-side), so subscribers tracking realized closures can observe forced fills on either `account` or `userFills`. ## AsyncAPI ````yaml api-reference/asyncapi.yaml userFills id: userFills title: User fills description: > > **Endpoint:** `wss://api.testnet.arcus.xyz/v1/ws` — one socket multiplexes every channel and RPC request. Click **Connect**, then send the example subscribe message below to start receiving data. Per-user fill stream. Snapshot on subscribe contains recent fills; streaming updates deliver each new fill as orders are matched. Snapshot is sent once on connect only. `LIQUIDATION` and `ADL` fills also appear here (taker-side), so subscribers tracking realized closures can observe forced fills on either `account` or `userFills`. servers: - id: testnet protocol: wss host: api.testnet.arcus.xyz bindings: [] variables: [] - id: mainnet protocol: wss host: api.arcus.xyz bindings: [] variables: [] address: /v1/ws?channel=userFills parameters: [] bindings: [] operations: - &ref_2 id: subscribeUserFills title: Subscribe user fills type: receive messages: - &ref_4 id: subscribe contentType: application/json payload: - name: Subscribe to an account channel type: object properties: - name: type type: string description: subscribe required: true - name: channel type: string enumValues: - account - positions - userFills - orders - funding - accountAttributeUpdates required: true - name: id type: string description: Master Ethereum address (0x-prefixed) or core account id. required: true - name: snapshot type: boolean description: >- When false, suppress the initial state snapshot on subscribe and stream only live updates (e.g. userFills, orders). Defaults to true. required: false headers: [] jsonPayloadSchema: type: object required: - type - channel - id properties: type: type: string const: subscribe x-parser-schema-id: channel: type: string enum: - account - positions - userFills - orders - funding - accountAttributeUpdates x-parser-schema-id: id: type: string description: Master Ethereum address (0x-prefixed) or core account id. example: 0xAbCd...1234 x-parser-schema-id: snapshot: type: boolean description: >- When false, suppress the initial state snapshot on subscribe and stream only live updates (e.g. userFills, orders). Defaults to true. default: true x-parser-schema-id: x-parser-schema-id: SubscribeByAddressPayload title: Subscribe to an account channel example: |- { "type": "subscribe", "channel": "account", "id": "0xAbCd...1234" } bindings: [] extensions: - id: x-parser-unique-object-id value: subscribe bindings: [] extensions: &ref_1 - id: x-parser-unique-object-id value: userFills - &ref_3 id: receiveUserFills title: Receive user fills type: send messages: - &ref_5 id: snapshot contentType: application/json payload: - name: User Fills Snapshot description: Recent fills sent once on subscribe. type: object properties: - name: type type: string description: >- `subscribed` for the initial snapshot; `channel_data` for updates. enumValues: - subscribed - channel_data required: true - name: channel type: string description: Channel name. required: true - name: id type: string description: Channel id (market or address). Absent for global channels. required: false - name: contents type: object description: Channel-specific payload. Schema varies by channel. required: false properties: [] headers: [] jsonPayloadSchema: &ref_0 type: object description: Common envelope for all server-pushed channel messages. required: - type - channel properties: type: type: string enum: - subscribed - channel_data description: >- `subscribed` for the initial snapshot; `channel_data` for updates. x-parser-schema-id: channel: type: string description: Channel name. x-parser-schema-id: id: type: string description: Channel id (market or address). Absent for global channels. x-parser-schema-id: contents: type: object additionalProperties: true description: Channel-specific payload. Schema varies by channel. properties: {} x-parser-schema-id: x-parser-schema-id: ChannelDataEnvelope title: User Fills Snapshot description: Recent fills sent once on subscribe. example: |- { "type": "", "channel": "", "id": "", "contents": {} } bindings: [] extensions: - id: x-parser-unique-object-id value: snapshot - &ref_6 id: update contentType: application/json payload: - name: User Fill Update description: One fill per frame as orders are matched. type: object properties: - name: type type: string description: >- `subscribed` for the initial snapshot; `channel_data` for updates. enumValues: - subscribed - channel_data required: true - name: channel type: string description: Channel name. required: true - name: id type: string description: Channel id (market or address). Absent for global channels. required: false - name: contents type: object description: Channel-specific payload. Schema varies by channel. required: false properties: [] headers: [] jsonPayloadSchema: *ref_0 title: User Fill Update description: One fill per frame as orders are matched. example: |- { "type": "", "channel": "", "id": "", "contents": {} } bindings: [] extensions: - id: x-parser-unique-object-id value: update bindings: [] extensions: *ref_1 sendOperations: - *ref_2 receiveOperations: - *ref_3 sendMessages: - *ref_4 receiveMessages: - *ref_5 - *ref_6 extensions: - id: x-parser-unique-object-id value: userFills securitySchemes: [] ````