> ## Documentation Index > Fetch the complete documentation index at: https://docs.itoflow.ai/llms.txt > Use this file to discover all available pages before exploring further. # Measure > Start measuring factor risk for 1 to 10 books over 1 to 60 dates of the factor model, on one model version: the one named, or the one live at the start. A book is a saved portfolio or a list of weights. model.as_of measures one date; model.range measures the last day of each month in it and its end (step month_end, the default) or each weekday (step daily); neither measures the newest publication. Each date reads the newest publication on or before it. Before the version's daily publications begin (model.dates.daily_from in an answer), a daily grid reads month-end publications, so use month_end for older history. A saved book without holdings_at follows its snapshots date by date; with holdings_at it stays the same book. Funds in a book, and the benchmark, are read through their stored holdings on or before each publication's model date. Answers 202 with a measure_id: read it until its status is not running. Keep the request_key: the same request with it joins the measure until 24 hours after it ends; another request with it is 409. A measure counts toward the 3 risk runs and measures an owner may have going, and stops if it runs past its time limit, at most 60 minutes; 429 and 503 carry Retry-After. For today's full report, start a risk run instead. Operation ID: startRiskMeasure. ## OpenAPI ````yaml /openapi/itoflow-public.openapi.json post /risk/measure openapi: 3.1.0 info: description: >- All Itoflow APIs are experimental and may change without notice. Read-only operations marked interactive can be tried from the documentation; the others are reference-only. title: Itoflow Developer API version: 1.0.0 servers: - description: Itoflow API url: https://api.itoflow.ai security: [] tags: - name: Account - name: Billing - name: Brokers - name: Chat - name: Connected MCP servers - name: GitHub - name: Market data - name: Monitors - name: Notifications - name: Portfolios - name: Risk runs - name: Sharing and data - name: Strategies paths: /risk/measure: post: tags: - Risk runs summary: Start a risk measure description: >- Start measuring factor risk for 1 to 10 books over 1 to 60 dates of the factor model, on one model version: the one named, or the one live at the start. A book is a saved portfolio or a list of weights. model.as_of measures one date; model.range measures the last day of each month in it and its end (step month_end, the default) or each weekday (step daily); neither measures the newest publication. Each date reads the newest publication on or before it. Before the version's daily publications begin (model.dates.daily_from in an answer), a daily grid reads month-end publications, so use month_end for older history. A saved book without holdings_at follows its snapshots date by date; with holdings_at it stays the same book. Funds in a book, and the benchmark, are read through their stored holdings on or before each publication's model date. Answers 202 with a measure_id: read it until its status is not running. Keep the request_key: the same request with it joins the measure until 24 hours after it ends; another request with it is 409. A measure counts toward the 3 risk runs and measures an owner may have going, and stops if it runs past its time limit, at most 60 minutes; 429 and 503 carry Retry-After. For today's full report, start a risk run instead. Operation ID: startRiskMeasure. operationId: startRiskMeasure requestBody: content: application/json: schema: $ref: '#/components/schemas/Gateway_RiskMeasureStart' required: true responses: '202': content: application/json: schema: $ref: '#/components/schemas/Gateway_startRiskMeasureResponse' description: Started, or joined the measure with this key and request headers: Cache-Control: schema: const: no-store type: string '400': content: application/json: schema: $ref: '#/components/schemas/Gateway_RiskMeasureError' description: >- invalid_request names the field: the shape, a limit, more than 60 dates, from after to, or a date after today in New York. headers: Cache-Control: schema: const: no-store type: string '401': content: application/json: schema: $ref: '#/components/schemas/Gateway_RiskMeasureError' description: No session or API bearer. headers: Cache-Control: schema: const: no-store type: string '404': content: application/json: schema: $ref: '#/components/schemas/Gateway_RiskMeasureError' description: 'portfolio_not_found: a portfolio that is missing or not yours.' headers: Cache-Control: schema: const: no-store type: string '409': content: application/json: schema: $ref: '#/components/schemas/Gateway_RiskMeasureError' description: >- risk_measure_request_key_conflict: this request_key started a measure of another request. headers: Cache-Control: schema: const: no-store type: string '429': content: application/json: schema: $ref: '#/components/schemas/Gateway_RiskMeasureError' description: 'risk_engine_busy: 3 risk runs or measures are going.' headers: Cache-Control: schema: const: no-store type: string Retry-After: description: Seconds to wait before calling again. schema: minimum: 1 type: integer '503': content: application/json: schema: $ref: '#/components/schemas/Gateway_RiskMeasureError' description: >- risk_engine_unavailable: the risk engine did not answer. Retry the same call; a start with the same request_key joins the measure it may have started. headers: Cache-Control: schema: const: no-store type: string Retry-After: description: Seconds to wait before calling again. schema: minimum: 1 type: integer security: - bearerAuth: [] components: schemas: Gateway_RiskMeasureStart: additionalProperties: false properties: request: $ref: '#/components/schemas/Gateway_RiskMeasureRequest' request_key: description: >- Your key for this measure. Retrying the same request with it joins the measure. maxLength: 200 minLength: 1 type: string required: - request_key - request type: object Gateway_startRiskMeasureResponse: additionalProperties: false properties: dates_total: maximum: 60 minimum: 1 type: integer joined_existing_measure: type: boolean measure_id: pattern: ^measure-[0-9a-f]{32}$ type: string status: description: running for a new measure; a joined one gives its own status. enum: - running - ok - failed type: string required: - measure_id - status - joined_existing_measure - dates_total type: object Gateway_RiskMeasureError: additionalProperties: false properties: error: additionalProperties: false properties: code: type: string details: additionalProperties: {} propertyNames: type: string type: object message: type: string required: - code - message type: object required: - error type: object Gateway_RiskMeasureRequest: additionalProperties: false properties: benchmark: description: >- A fund, such as SPY.US. Its stored holdings book on or before the publication's model date gives each book active risk; without one, active is null and a warning says why. maxLength: 32 minLength: 1 type: string books: description: 1 to 10 books, each a saved portfolio or a list of weights. items: anyOf: - additionalProperties: false properties: label: description: Your name for the book. Labels are unique within a call. maxLength: 80 minLength: 1 type: string portfolio: additionalProperties: false properties: holdings_at: anyOf: - format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d(?:\.\d+)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$ type: string - pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$ type: string description: >- A time with its offset, such as 2026-07-31T20:00:00Z. The book is the newest saved snapshot on or before it. Omitted with no as_of or range: the newest snapshot at the measure's start time, shared by every book. A dated request uses the end of the publication's model date in New York. portfolio_id: description: A saved portfolio you own. format: uuid pattern: >- ^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$ type: string required: - portfolio_id type: object required: - label - portfolio type: object - additionalProperties: false properties: holdings: description: >- 1 to 3000 lines, as fractions of net assets. With a CASH line the weights add to 1, within 0.01. Without one, the rest of the book is cash; a book that borrows lists CASH below zero. Nothing is rescaled. items: additionalProperties: false properties: symbol: description: >- Ticker symbol such as NVDA.US; a bare ticker means its US listing. CASH is US dollars. maxLength: 32 minLength: 1 type: string weight: description: >- Fraction of the portfolio's net assets, so 0.25 is 25%. A short is below zero, and CASH holds what its sale raised. type: number required: - symbol - weight type: object maxItems: 3000 minItems: 1 type: array label: description: Your name for the book. Labels are unique within a call. maxLength: 80 minLength: 1 type: string required: - label - holdings type: object maxItems: 10 minItems: 1 type: array model: additionalProperties: false default: {} description: >- Which dates of the factor model to measure on. Neither as_of nor range: the version's newest publication. properties: as_of: description: >- One date, YYYY-MM-DD, not after today in New York. The newest publication on or before it counts. Not with range. format: date pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))$ type: string range: additionalProperties: false description: >- A range of model dates, at most 60. Each date reads the newest publication on or before it. properties: from: description: YYYY-MM-DD, on or before to. format: date pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))$ type: string step: default: month_end description: >- month_end: the last day of each month in the range, and to when it is not one. daily: each weekday in the range. enum: - month_end - daily type: string to: description: YYYY-MM-DD, not after today in New York. format: date pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))$ type: string required: - from - to type: object version: description: >- A factor model version. Omitted: the version live when the measure starts. Every date uses it. maxLength: 200 minLength: 1 type: string type: object top_names: default: 10 description: How many names to list by their share of each book's risk, 0 to 50. maximum: 50 minimum: 0 type: integer required: - books type: object securitySchemes: bearerAuth: bearerFormat: JWT description: Itoflow access token issued for the Itoflow API. scheme: bearer type: http ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.