API ReferenceVolatility & Positioning
VIX futures curve
/api/v3/volatility/vx_curve- Plan
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volatility_vx_ curve
VIX FUTURES CURVE: the monthly VIX futures' daily settlements for one session (contract_month, expiration, days_to_expiration, settlement in VIX index points; 1 point = USD 1,000 per contract) and its term structure: front, second and back month, second_over_front_pct (percent) and state = contango (second above front, the usual state) or backwardation (front above second, typical of stress). history gives the last N sessions' front, second, back and state. Default the newest session (one per trading day, written that evening); date=YYYY-MM-DD for an earlier one (404 with the nearest prior session if none). History from August 2026. On a contract's expiry day its final settlement is served apart (final_settlement) and the front is the next contract. Rows captured before 2026-09-25 name only the contract month and are withheld and counted (coverage.withheld_rows); non-trading days and sessions that repeat the prior one are withheld and listed. freshness.sessions_behind and stale label a late feed.
Parameters
Query
datestringOptionalSession YYYY-MM-DD; omit for the newest.
historyintegerOptionalSessions of term-structure history ending at the served session.
200 to 250Response
A 200 is a JSON envelope: ok: true and this endpoint's own fields (see Macro, Rates & FX). It carries X-Request-ID, the credit headers (X-Credits-Cost, X-Credits-Remaining, X-Credits-Receipt, X-Credits-Settlement) and the rate-limit headers.
A 200 is billed even when it holds no data (an empty list, null, found: false), so check those fields. Pricing & credits explains the credit headers.
Errors
No error is billed. The body is { "ok": false, "error", "detail", "request_; read the code from error.
| Error | Meaning |
|---|---|
400 invalid_ticker | The request is malformed, for example a ticker that is not a symbol: invalid_ticker, refused before any credit is reserved, with param naming the parameter. Not billed. |
401 unauthorized | Missing or invalid API key. |
402 plan_required | Your plan does not include this tool, you are out of credits, or your workspace's spend cap paused its keys. plan_required names the plan that unlocks the tool; usage_exceeded means the credit balance is spent; spend_cap_reached means the key is paused until the cap resets or is raised: detail names the cap and the reset, cap_usd and resets_at (ISO 8601) carry them, and doc_url links pricing and credits. Not billed. |
403 scope_denied | This API key is limited to some products and this tool is not one of them. product names the tool's product and scopes the key's products. An upgrade does not change it: use a key whose scopes include the product, or change this key's scopes. Not billed. |
404 not_found | No such resource. Not billed. |
422 validation | A parameter is missing, out of range or the wrong type; param names it. Not billed. |
429 rate_limited | Your plan's rate limit is spent for this window. Retry after Retry-After seconds. Not billed. |
503 paid_ | The data could not be served completely right now; retry later. Not billed. |
504 request_timeout | The request ran past the server's time budget; retry. Not billed. |
This table lists what the spec declares for this route. Error responses lists every code FIRM sends, with when to retry.
Guides
Read the Macro, Rates & FX guide for this endpoint's fields and examples.