> ## Documentation Index > Fetch the complete documentation index at: https://docs.agg.market/llms.txt > Use this file to discover all available pages before exploring further. # Arb > Subscribe to per-market arb-return updates. Send `{ action: "subscribe", channel: "arb", marketIds: string[] }`. The server echos subscribed marketIds in the `subscribed` reply. No initial snapshot — updates arrive as `arb_market_update` messages when the engine detects a change. ## AsyncAPI ````yaml openapi/asyncapi.json arb id: arb title: Arb description: >- Subscribe to per-market arb-return updates. Send `{ action: "subscribe", channel: "arb", marketIds: string[] }`. The server echos subscribed marketIds in the `subscribed` reply. No initial snapshot — updates arrive as `arb_market_update` messages when the engine detects a change. servers: - id: production protocol: wss host: ws.agg.market bindings: [] variables: [] address: / parameters: [] bindings: [] operations: - &ref_2 id: subscribeArb title: Subscribe arb description: Subscribe to arb-return updates for specific markets type: send messages: - &ref_5 id: subscribe payload: - name: Subscribe to orderbook description: Subscribe to aggregated orderbook updates for markets type: object properties: - name: action type: string description: subscribe required: true - name: channel type: string required: true - name: outcomeIds type: array description: Outcome IDs to subscribe to required: true properties: - name: item type: string required: false headers: [] jsonPayloadSchema: title: Subscribe type: object required: - action - channel - outcomeIds properties: action: const: subscribe type: string x-parser-schema-id: channel: anyOf: - const: orderbook type: string x-parser-schema-id: - const: trades type: string x-parser-schema-id: x-parser-schema-id: outcomeIds: description: Outcome IDs to subscribe to type: array items: type: string x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Subscribe to orderbook description: Subscribe to aggregated orderbook updates for markets example: |- { "action": "subscribe", "channel": "orderbook", "outcomeIds": [ "clv2abc123def456", "clv2xyz789ghi012" ] } bindings: [] extensions: - id: x-parser-unique-object-id value: subscribe bindings: [] extensions: &ref_0 - id: x-parser-unique-object-id value: arb - &ref_3 id: unsubscribeArb title: Unsubscribe arb description: Unsubscribe from arb-return updates for specific markets type: send messages: - &ref_6 id: unsubscribe payload: - name: Unsubscribe from orderbook type: object properties: - name: action type: string description: unsubscribe required: true - name: channel type: string required: true - name: outcomeIds type: array description: Outcome IDs to unsubscribe from required: true properties: - name: item type: string required: false headers: [] jsonPayloadSchema: title: Unsubscribe type: object required: - action - channel - outcomeIds properties: action: const: unsubscribe type: string x-parser-schema-id: channel: anyOf: - const: orderbook type: string x-parser-schema-id: - const: trades type: string x-parser-schema-id: x-parser-schema-id: outcomeIds: description: Outcome IDs to unsubscribe from type: array items: type: string x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Unsubscribe from orderbook example: |- { "action": "unsubscribe", "channel": "orderbook", "outcomeIds": [ "clv2abc123def456", "clv2xyz789ghi012" ] } bindings: [] extensions: - id: x-parser-unique-object-id value: unsubscribe bindings: [] extensions: *ref_0 - &ref_1 id: receiveArbMarketUpdate title: Receive arb market update description: Arb-return update for a subscribed market type: receive messages: - &ref_4 id: arbMarketUpdate payload: - name: Arb-return update for a specific market description: >- Pushed to clients subscribed to { channel: "arb", marketIds } when the engine detects a new arbReturn value for that market. type: object properties: - name: type type: string description: arb_market_update required: true - name: marketId type: string required: true - name: activeVenuesOnly type: boolean description: Producer assertion that globally inactive venues were excluded required: true - name: venueEventId type: string required: true - name: arbReturn type: number required: true - name: ts type: number required: true - name: liquidityUsd type: number required: false - name: liquidityTier type: string required: false headers: [] jsonPayloadSchema: title: ArbMarketUpdate type: object required: - type - marketId - activeVenuesOnly - venueEventId - arbReturn - ts properties: type: const: arb_market_update type: string x-parser-schema-id: marketId: type: string x-parser-schema-id: activeVenuesOnly: description: Producer assertion that globally inactive venues were excluded const: true type: boolean x-parser-schema-id: venueEventId: anyOf: - type: string x-parser-schema-id: - type: 'null' x-parser-schema-id: x-parser-schema-id: arbReturn: type: number x-parser-schema-id: ts: type: number x-parser-schema-id: liquidityUsd: type: number x-parser-schema-id: liquidityTier: anyOf: - const: deep type: string x-parser-schema-id: - const: shallow type: string x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Arb-return update for a specific market description: >- Pushed to clients subscribed to { channel: "arb", marketIds } when the engine detects a new arbReturn value for that market. example: |- { "type": "arb_market_update", "marketId": "mkt_abc123", "activeVenuesOnly": true, "venueEventId": "evt_xyz789", "arbReturn": 0.05, "ts": 1710000000000, "liquidityUsd": 0, "liquidityTier": "deep" } bindings: [] extensions: - id: x-parser-unique-object-id value: arbMarketUpdate bindings: [] extensions: *ref_0 sendOperations: - *ref_1 receiveOperations: - *ref_2 - *ref_3 sendMessages: - *ref_4 receiveMessages: - *ref_5 - *ref_6 extensions: - id: x-parser-unique-object-id value: arb securitySchemes: - id: appId name: appId type: userPassword description: >- App-level auth: pass appId as a query parameter on connect. Required for all connections. The appId must belong to an active app with matching allowed origins. extensions: [] - id: jwt name: jwt type: http description: >- User-level auth: pass JWT as token query param on connect, or send { action: 'authenticate', token } mid-session. Required for user-specific events (orders, balances). Same JWT as the REST API. scheme: bearer bearerFormat: JWT extensions: [] ````