> ## Documentation Index > Fetch the complete documentation index at: https://docs.sandmark.com/llms.txt > Use this file to discover all available pages before exploring further. # Implied volatility > Continuous constant-maturity implied volatility for one tenor, delta and option type. Each point is interpolated in total variance between the two listed expiries that bracket the tenor, so the series never jumps on an expiry roll. Values are decimal (0.37 = 37 vol points). **History window.** How far back you can read depends on your billing plan: 1 month on monthly billing, 1 year on quarterly, 3 years on annual. A `start` earlier than your window (or no `start` at all) is moved forward to the window start, and the `Sandmark-Data-Window-Start` response header says where it began. An `end` before the window start returns `403`. > [!TIP] > > New to the series? [Continuous implied volatility](https://docs.sandmark.com/concepts/implied-volatility.md) explains what one point > means and how it is built. ## OpenAPI ````yaml GET /v1/timeseries/iv openapi: 3.0.3 info: title: Sandmark Volatility API version: 1.0.0 description: >- Continuous implied and realised volatility for crypto options, with the reference data to query it. contact: name: Sandmark url: https://sandmark.com servers: - url: https://api.sandmark.com/volatility description: Production security: - apiKey: [] tags: - name: Reference description: Assets, frequencies and expiries. - name: Timeseries description: Continuous IV and RV series. paths: /v1/timeseries/iv: get: tags: - Timeseries summary: Implied volatility description: >- Continuous constant-maturity implied volatility for one tenor, delta and option type. Each point is interpolated in total variance between the two listed expiries that bracket the tenor, so the series never jumps on an expiry roll. Values are decimal (0.37 = 37 vol points). **History window.** How far back you can read depends on your billing plan: 1 month on monthly billing, 1 year on quarterly, 3 years on annual. A `start` earlier than your window (or no `start` at all) is moved forward to the window start, and the `Sandmark-Data-Window-Start` response header says where it began. An `end` before the window start returns `403`. operationId: getImpliedVolTimeseries parameters: - name: asset in: query required: true schema: type: string enum: - DER.BTC_USD - DER.ETH_USD - DER.BTC_USDC - DER.ETH_USDC - DER.SOL_USDC - DER.XRP_USDC - DER.AVAX_USDC - DER.TRX_USDC - DER.HYPE_USDC - OKX.BTC_USD - OKX.ETH_USD - BIN.BTC_USDT - BIN.ETH_USDT - BYB.BTC_USDT - BYB.ETH_USDT description: >- Underlying identifier, `VENUE.BASE_QUOTE`. `DER` is Deribit; `OKX`, `BIN` (Binance) and `BYB` (Bybit) are the other venues. `DER.BTC_USD` and `DER.ETH_USD` are the inverse contracts and carry the deepest history; the `_USDC` underlyings are linear. example: DER.BTC_USD - name: frequency in: query required: true schema: type: string enum: - 1h description: >- Sampling frequency of the stored series. `GET /v1/frequencies` lists the available values. example: 1h - name: option_type in: query required: true schema: type: string enum: - C - P description: >- `C` for calls, `P` for puts. At 50 delta both legs carry the same IV. example: C - name: tenor_label in: query required: true schema: type: string enum: - 1d - 1w - 2w - 1m - 2m - 3m - 6m - 9m - 1y description: >- Constant-maturity tenor: `1d`, `1w`, `2w`, `1m`, `2m`, `3m`, `6m`, `9m` or `1y`. example: 1m - name: delta_target_pct in: query required: true schema: type: integer enum: - 5 - 10 - 15 - 20 - 25 - 30 - 35 - 40 - 45 - 50 description: >- Absolute delta in percent. `50` is at-the-money; `25` with `P` is the 25-delta put. example: 50 - name: start in: query required: false schema: type: string format: date-time description: >- Inclusive lower bound, ISO 8601 UTC (for example `2026-11-01T00:00:00Z`). Defaults to the start of your history window. example: '2026-10-20T00:00:00Z' - name: end in: query required: false schema: type: string format: date-time description: >- Inclusive upper bound, ISO 8601 UTC. Defaults to the latest stored observation. example: '2026-11-01T00:00:00Z' - name: limit in: query required: false schema: type: integer minimum: 1 maximum: 5000 default: 500 description: >- Maximum rows to return. Rows are ordered **newest first**, so `limit` keeps the most recent observations inside `start`..`end`. Page backwards by moving `end`. - name: iv_source_col in: query required: false schema: type: string enum: - IV_MARK - IV_MARK_COMPUTED default: IV_MARK description: >- Which published vol surface to read. `IV_MARK` is the default and the surface used across Sandmark. `IV_MARK_COMPUTED` is the alternative surface; the two differ by about 0.08 vol points on average. Keep one value for a whole analysis. responses: '200': description: OK content: application/json: schema: $ref: '#/components/schemas/IvSeriesResponse' example: series: iv row_count: 2 data: - UNDERLYING_ID: DER.BTC_USD DATETIME: '2026-11-06T22:00:00Z' OPTION_TYPE: C FREQUENCY: 1h TENOR_LABEL: 1m TENOR_DAYS: 30 DELTA_TARGET: 0.5 DELTA_TARGET_PCT: 50 DTE: 30 DELTA: 0.5036 IV: 0.3732 IV_LO: 0.3688 IV_HI: 0.3767 DTE_LO: 20.42 DTE_HI: 48.42 ATM_DIST: 0.0036 METHODOLOGY: total_variance_interp METHOD: iv_C_50_delta_30d METRIC_FAMILY: continuous_iv IV_SOURCE_COL: IV_MARK LOAD_TS: '2026-11-06T22:25:28' - UNDERLYING_ID: DER.BTC_USD DATETIME: '2026-11-06T21:00:00Z' OPTION_TYPE: C FREQUENCY: 1h TENOR_LABEL: 1m TENOR_DAYS: 30 DELTA_TARGET: 0.5 DELTA_TARGET_PCT: 50 DTE: 30 DELTA: 0.5021 IV: 0.3719 IV_LO: 0.3671 IV_HI: 0.3758 DTE_LO: 20.46 DTE_HI: 48.46 ATM_DIST: 0.0021 METHODOLOGY: total_variance_interp METHOD: iv_C_50_delta_30d METRIC_FAMILY: continuous_iv IV_SOURCE_COL: IV_MARK LOAD_TS: '2026-11-06T21:25:31' headers: Sandmark-Data-Window-Start: description: >- Earliest timestamp your plan can read, ISO 8601 UTC. Use it to tell a clamped `start` from a real gap in the data. schema: type: string format: date-time '400': description: '`start` or `end` is not a valid ISO 8601 timestamp.' content: application/json: schema: $ref: '#/components/schemas/Error' example: statusCode: 400 message: >- start must be an ISO 8601 timestamp such as 2026-11-01T00:00:00Z; got 'yesterday' '401': description: Missing or invalid API key. content: application/json: schema: $ref: '#/components/schemas/Error' example: statusCode: 401 message: >- Access denied due to missing subscription key. Make sure to include subscription key when making requests to an API. '403': description: '`end` falls before the start of your data window.' content: application/json: schema: $ref: '#/components/schemas/Error' example: statusCode: 403 message: >- end is before your data window, which starts at 2026-10-07T23:00:00Z '422': description: A parameter failed validation. `detail` names the field. content: application/json: schema: $ref: '#/components/schemas/ValidationError' '429': description: >- Rate limit exceeded. Retry after the number of seconds in `Retry-After`. content: application/json: schema: $ref: '#/components/schemas/Error' example: statusCode: 429 message: Rate limit is exceeded. Try again in 12 seconds. components: schemas: IvSeriesResponse: type: object required: - series - row_count - data properties: series: type: string enum: - iv row_count: type: integer description: Number of rows in `data`. data: type: array items: $ref: '#/components/schemas/IvRow' description: Newest first. Error: type: object properties: statusCode: type: integer example: 403 message: type: string required: - statusCode - message ValidationError: type: object properties: detail: type: array items: type: object properties: loc: type: array items: type: string msg: type: string type: type: string IvRow: type: object properties: UNDERLYING_ID: type: string example: DER.BTC_USD DATETIME: type: string format: date-time description: Bar close, UTC. OPTION_TYPE: type: string enum: - C - P FREQUENCY: type: string example: 1h TENOR_LABEL: type: string example: 1m TENOR_DAYS: type: number description: Constant-maturity tenor in days. DELTA_TARGET_PCT: type: integer example: 25 DELTA_TARGET: type: number example: 0.25 DELTA: type: number description: Delta actually achieved by the interpolated point. DTE: type: number description: Days to expiry of the constant-maturity point (equals `TENOR_DAYS`). IV: type: number description: Implied volatility, **decimal** (0.37 = 37%). IV_LO: type: number description: IV of the listed expiry just before the tenor. IV_HI: type: number description: IV of the listed expiry just after the tenor. DTE_LO: type: number description: Days to expiry of the bracketing expiry before the tenor. DTE_HI: type: number description: Days to expiry of the bracketing expiry after the tenor. ATM_DIST: type: number description: Distance between achieved and target delta. METHODOLOGY: type: string example: total_variance_interp METHOD: type: string example: iv_C_50_delta_30d METRIC_FAMILY: type: string example: continuous_iv IV_SOURCE_COL: type: string enum: - IV_MARK - IV_MARK_COMPUTED LOAD_TS: type: string description: When the row was written, UTC. securitySchemes: apiKey: type: apiKey in: header name: X-API-Key description: Your Sandmark API key. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.