Next OpEx Date

OpEx is a calendar label, but the useful trading object is a listed contract. The standard monthly cycle is the third-Friday anchor that most people mean when they ask when OpEx is this month. Weekly options can create additional expirations around the same window, while index products such as SPXW can add even more short-dated expirations. That means the right workflow is two-stage: use the calendar to understand the cycle, then ask the API which expirations are actually listed for the ticker.

The distinction matters in backtests and scanners. A model that assumes every Friday exists for every underlying will create invalid chain requests, and a model that treats a quarterly OpEx exactly like a normal weekly date can miss the open-interest concentration that often changes liquidity, spreads, and dealer hedging behavior. The calendar answer gets you oriented; listed expirations keep the implementation falsifiable.

A robust expiration widget should first request listed dates, then classify them relative to the standard monthly calendar, and only then request chains or contracts. This keeps the UI stable when a symbol has unusual listing depth, when a holiday moves the standard cycle, or when a ticker has no contracts on a date that a generic calendar would otherwise suggest.

curl "https://api.cutemarkets.com/v1/tickers/expirations/SPY/" \
  -H "Authorization: Bearer YOUR_API_KEY"

curl "https://api.cutemarkets.com/v1/options/chain/SPY/?expiration_date=2026-05-15&limit=100" \
  -H "Authorization: Bearer YOUR_API_KEY"