> ## 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. # Exchange attribute updates > > **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. Exchange-wide attribute state, discriminated by entry `type`. Currently the only entry type is `"feeTierConfig"`, which carries the full fee tier table whenever an operator updates it via `PUT /internal/feetiers` or `POST /internal/feetiers/{level}`. **Global channel — no `id` required.** All subscribers receive the same stream. On subscribe: snapshot of the current fee tier table (one `feeTierConfig` entry, `isSnapshot: true`). Streaming: whenever the operator edits the fee tier config, go-core confirms the change and go-socks broadcasts a full table replacement (`isSnapshot: false`). The equivalent REST read is `GET /v1/feetiers`. ## AsyncAPI ````yaml api-reference/asyncapi.yaml exchangeAttributeUpdates id: exchangeAttributeUpdates title: Exchange attribute updates 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. Exchange-wide attribute state, discriminated by entry `type`. Currently the only entry type is `"feeTierConfig"`, which carries the full fee tier table whenever an operator updates it via `PUT /internal/feetiers` or `POST /internal/feetiers/{level}`. **Global channel — no `id` required.** All subscribers receive the same stream. On subscribe: snapshot of the current fee tier table (one `feeTierConfig` entry, `isSnapshot: true`). Streaming: whenever the operator edits the fee tier config, go-core confirms the change and go-socks broadcasts a full table replacement (`isSnapshot: false`). The equivalent REST read is `GET /v1/feetiers`. 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=exchangeAttributeUpdates parameters: [] bindings: [] operations: - &ref_3 id: subscribeExchangeAttributes title: Subscribe exchange attributes type: receive messages: - &ref_5 id: subscribe contentType: application/json payload: - name: Subscribe to the exchange attribute updates channel type: object properties: - name: type type: string description: subscribe required: true - name: channel type: string description: exchangeAttributeUpdates required: true - name: snapshot type: boolean description: >- When false, suppress the initial state snapshot on subscribe and stream only live updates. Defaults to true. required: false headers: [] jsonPayloadSchema: type: object required: - type - channel properties: type: type: string const: subscribe x-parser-schema-id: channel: type: string const: exchangeAttributeUpdates x-parser-schema-id: snapshot: type: boolean description: >- When false, suppress the initial state snapshot on subscribe and stream only live updates. Defaults to true. default: true x-parser-schema-id: x-parser-schema-id: SubscribeExchangeAttributeUpdatesPayload title: Subscribe to the exchange attribute updates channel example: |- { "type": "subscribe", "channel": "exchangeAttributeUpdates" } bindings: [] extensions: - id: x-parser-unique-object-id value: subscribe bindings: [] extensions: &ref_2 - id: x-parser-unique-object-id value: exchangeAttributeUpdates - &ref_4 id: receiveExchangeAttributes title: Receive exchange attributes type: send messages: - &ref_6 id: snapshot contentType: application/json payload: - allOf: &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 - type: object properties: contents: type: object required: - isSnapshot - entries properties: isSnapshot: type: boolean description: > True for the subscribe-time snapshot; false for streaming updates triggered by operator fee tier edits. x-parser-schema-id: entries: type: array items: type: object description: > A discriminated-union entry in the exchangeAttributeUpdates stream. Currently the only defined `type` is `"feeTierConfig"`. required: - type properties: type: type: string enum: - feeTierConfig description: >- Discriminator. `"feeTierConfig"` carries the full fee tier table. x-parser-schema-id: tiers: type: array items: type: object description: >- One tier row in a feeTierConfig exchange attribute entry. required: - level - name - volumeThreshold - makerFeeBps - takerFeeBps properties: level: type: integer format: uint8 description: > Tier level index (0=Base, 1=Bronze, 2=Silver, 3=Gold, 4=Platinum, 5=VIP, 6=Max). x-parser-schema-id: name: type: string description: >- Human-readable tier name (e.g. "Base", "Gold"). x-parser-schema-id: volumeThreshold: type: integer format: int64 description: > 30-day notional volume threshold in USD×1e6 required to reach this tier. Always 0 for the base tier. x-parser-schema-id: makerFeeBps: type: integer format: int32 description: > Maker fee rate in ppm — parts-per-million of notional (e.g. 200 = 0.02% = 2 bps). Negative values indicate a maker rebate. x-parser-schema-id: takerFeeBps: type: integer format: int32 description: > Taker fee rate in ppm — parts-per-million of notional (e.g. 500 = 0.05% = 5 bps). Always ≥ 0. x-parser-schema-id: x-parser-schema-id: ExchangeAttributesFeeTierTier description: > Present when `type` is `"feeTierConfig"`. Full replacement of the exchange fee tier table, sorted ascending by level. x-parser-schema-id: x-parser-schema-id: ExchangeAttributesEntry x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: ExchangeAttributesUpdatePayload name: Exchange Attributes Snapshot description: > Initial snapshot sent once on subscribe. Contains one `feeTierConfig` entry with the complete current fee tier table (`isSnapshot: true`). headers: [] jsonPayloadSchema: &ref_1 allOf: *ref_0 x-parser-schema-id: ExchangeAttributesUpdatePayload title: Exchange Attributes Snapshot description: > Initial snapshot sent once on subscribe. Contains one `feeTierConfig` entry with the complete current fee tier table (`isSnapshot: true`). example: |- { "type": "subscribed", "channel": "exchangeAttributeUpdates", "id": "", "contents": { "isSnapshot": true, "entries": [ { "type": "feeTierConfig", "tiers": [ { "level": 0, "name": "Base", "volumeThreshold": 0, "makerFeeBps": 200, "takerFeeBps": 500 }, { "level": 1, "name": "Bronze", "volumeThreshold": 100000000000, "makerFeeBps": 150, "takerFeeBps": 450 } ] } ] } } bindings: [] extensions: - id: x-parser-unique-object-id value: snapshot - &ref_7 id: update contentType: application/json payload: - allOf: *ref_0 x-parser-schema-id: ExchangeAttributesUpdatePayload name: Exchange Attributes Update description: > Streaming update pushed whenever an operator edits the exchange fee tier config. Always carries the full updated table in a single `feeTierConfig` entry (`isSnapshot: false`). Clients should replace their local copy atomically. headers: [] jsonPayloadSchema: *ref_1 title: Exchange Attributes Update description: > Streaming update pushed whenever an operator edits the exchange fee tier config. Always carries the full updated table in a single `feeTierConfig` entry (`isSnapshot: false`). Clients should replace their local copy atomically. example: |- { "type": "channel_data", "channel": "exchangeAttributeUpdates", "id": "", "contents": { "isSnapshot": false, "entries": [ { "type": "feeTierConfig", "tiers": [ { "level": 0, "name": "Base", "volumeThreshold": 0, "makerFeeBps": 200, "takerFeeBps": 500 } ] } ] } } bindings: [] extensions: - id: x-parser-unique-object-id value: update bindings: [] extensions: *ref_2 sendOperations: - *ref_3 receiveOperations: - *ref_4 sendMessages: - *ref_5 receiveMessages: - *ref_6 - *ref_7 extensions: - id: x-parser-unique-object-id value: exchangeAttributeUpdates securitySchemes: [] ````