> ## Documentation Index > Fetch the complete documentation index at: https://docs.omnibook.xyz/llms.txt > Use this file to discover all available pages before exploring further. # A market's current round > One market's current round in any status. Never-opened or evicted-past-ring ⇒ 404 `round_not_found`. ## OpenAPI ````yaml /api-spec/venue-openapi.yaml get /v1/rounds/{market_id} openapi: 3.1.0 info: title: Exchange API — REST lane version: 1.0.0 summary: Client-facing REST surface for the binary prediction-market exchange. description: | The client-visible REST contract of the API lane. ## Conventions - **Versioning:** every path is under `/v1/`. Unknown *request* fields are rejected (`400 unknown_field`); clients MUST ignore unknown *response* fields (additive changes are non-breaking). - **Numbers:** prices are integer **ticks** (1–99, cents); quantities are integer shares; money is integer cents. u64-domain values (`order_id`, `client_order_id`, `seq`, cents amounts, timestamps) render as decimal **strings**; u32-and-below render as JSON numbers. Floats never appear. - **Timestamps:** `ts`/`*_ts` fields are nanoseconds since the Unix epoch as decimal strings — the sequencer's stamp, untranslated. - **`as_of_seq`:** every read response carries the stream sequence number its answer is current as of. Two reads with the same `as_of_seq` describe one consistent instant. - **Pagination:** list endpoints take `limit` (default 100, max 1000) and an opaque `cursor`; responses echo `cursor` for the next page (empty string when exhausted). ## Authentication Every request — there is no anonymous surface — carries three headers: `DX-ACCESS-KEY`, `DX-ACCESS-TIMESTAMP` (Unix ms), and `DX-ACCESS-SIGNATURE` (base64 HMAC-SHA256 over the canonical string `timestamp + "\n" + METHOD + "\n" + path?query + "\n" + body`, ±5000 ms replay window). Keys carry scopes `read` (GETs), `trade` (order mutations), and `withdraw` (`POST /v1/withdrawals`); the required scope per operation is given in `x-required-scope`. Rate limits are per-key token buckets (read 100/s +200 burst; write 50/s +100 burst) answered with `429 rate_limited` whose body carries `details.retry_after_ms` (decimal-string milliseconds — no `Retry-After` header in v1). ## Execution outcomes are not errors Post-only cross, FOK infeasible, IOC remainder, STP and max-cost-infeasible arrive as a **successful** placement response with `status: "canceled"` and a `reason` — they are the order's history, not a protocol failure. Only the reject taxonomy maps to non-2xx. x-other-lanes: websocket: endpoint: wss://{host}/v1/ws note: >- AsyncAPI territory — subscribe/unsubscribe command envelope, public channels (orderbook_delta, trades, oracle, rounds) and the private `user` channel with snapshot+resume. `ticker` is deferred (wscode 4). Not modelled in this OpenAPI document. mcp: endpoint: POST /v1/mcp note: >- JSON-RPC 2.0 agent lane exposing the same reads/writes as MCP tools. Described by its own tool schema, not OpenAPI. servers: - url: https://api.omnibook.xyz description: >- Production. Every request is authenticated — there is no anonymous access, including market data. See Authentication. security: - DxAccessKey: [] DxAccessTimestamp: [] DxAccessSignature: [] tags: - name: Exchange description: Exchange-wide control state and retention caps. - name: Account description: The authenticated key's own scopes and rate limits. - name: Markets description: Market metadata, orderbooks, public tape, oracle and rounds. - name: Portfolio (read) description: Key-scoped balance, positions, fills and orders. - name: Orders (write) description: Order placement, cancel, decrease, batch, cancel-batch and cancel-all. - name: Funding description: Deposit address and withdrawals. - name: Admin description: > Control-plane operator actions. Served on a SEPARATE listener from every path above — see the operation's own `servers` override; the top-level `servers` block does not reach it. externalDocs: description: Normative API surface specification (REST + WebSocket). url: https://docs.omnibook.xyz/ paths: /v1/rounds/{market_id}: get: tags: - Markets summary: A market's current round description: | One market's current round in any status. Never-opened or evicted-past-ring ⇒ 404 `round_not_found`. operationId: getRound parameters: - $ref: '#/components/parameters/MarketIdPath' responses: '200': description: The round object plus `as_of_seq`. content: application/json: schema: allOf: - $ref: '#/components/schemas/Round' - $ref: '#/components/schemas/AsOfSeq' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/MissingScope' '404': description: '`round_not_found` — unknown market, never opened, or evicted.' content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' example: error: code: round_not_found num: null origin: gateway message: round_not_found details: null '429': $ref: '#/components/responses/RateLimited' components: parameters: MarketIdPath: name: market_id in: path required: true schema: type: integer schemas: Round: type: object description: A round object. properties: market_id: type: integer status: type: string enum: - trading - frozen - proposed - settled - void strike: allOf: - $ref: '#/components/schemas/U64String' description: Open price @1e8. settle_price: allOf: - $ref: '#/components/schemas/U64String' description: Freeze price @1e8. winner: oneOf: - $ref: '#/components/schemas/Outcome' - type: 'null' description: Outcome once decided; null while trading/frozen. yes_payout: type: integer description: u8 cents-per-$1 for YES holders fresh_source_count_at_freeze: type: integer description: u8 count at freeze gen: type: integer open_ts: $ref: '#/components/schemas/U64String' freeze_ts: $ref: '#/components/schemas/U64String' resolve_ts: $ref: '#/components/schemas/U64String' round_number: $ref: '#/components/schemas/U64String' generation: type: integer description: market slot generation (order-binding epoch) category: type: integer description: series/category id (0 = unclassified) twap_window_secs: type: integer description: per-series settle TWAP window required: - market_id - status - strike - settle_price - winner - yes_payout - fresh_source_count_at_freeze - gen - open_ts - freeze_ts - resolve_ts - round_number - generation - category - twap_window_secs AsOfSeq: type: object properties: as_of_seq: allOf: - $ref: '#/components/schemas/U64String' - description: Stream sequence this answer is current as of. required: - as_of_seq ErrorEnvelope: type: object description: The uniform error body. properties: error: type: object properties: code: type: string description: lowercase snake_case reject/gateway code. num: type: - integer - 'null' description: >- The u16 reject code; non-null iff origin is `core` or `port` drawing from the shared registry (funding-port rejects carry a null num). origin: type: string enum: - core - port - gateway message: type: string details: type: - object - 'null' required: - code - num - origin - message - details required: - error U64String: type: string description: A u64-domain value rendered as a decimal string. pattern: ^[0-9]+$ example: '182390' Outcome: type: string enum: - 'yes' - 'no' responses: Unauthorized: description: Missing or invalid signature (`unauthorized`, origin gateway). content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' example: error: code: unauthorized num: null origin: gateway message: unauthorized details: null MissingScope: description: >- Key lacks the required scope (`missing_scope`), or a risk reject (`per_market_limit`, `user_suspended`, `reduce_only_violation`, …). content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' example: error: code: missing_scope num: null origin: gateway message: missing_scope details: null RateLimited: description: | Token bucket empty (`rate_limited`). Retry after `error.details.retry_after_ms` milliseconds (decimal string). v1 does not emit a `Retry-After` HTTP header. content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' example: error: code: rate_limited num: null origin: gateway message: rate limited details: retry_after_ms: '10' securitySchemes: DxAccessKey: type: apiKey in: header name: DX-ACCESS-KEY description: The public API key (alphanumeric access_key string). DxAccessTimestamp: type: apiKey in: header name: DX-ACCESS-TIMESTAMP description: Request timestamp, Unix milliseconds (decimal). ±5000 ms replay window. DxAccessSignature: type: apiKey in: header name: DX-ACCESS-SIGNATURE description: > base64(HMAC-SHA256(secret, "timestamp\nMETHOD\npath?query\nbody")). For the WS handshake the body is empty and the path is `/v1/ws`. ````