API Reference

RSI measures momentum on a 0–100 scale, commonly with a window such as 14 periods.

Use RSI with Aggregates, Options Chain API, Historical Options Data API, Backtesting Data Quality Checklist, and Stock Aggregates and Indicators.

For query parameters, response envelope, expand_underlying, request_id, and pagination (next_url / page), see SMA. Use window for the RSI lookback length.

Endpoint

GET /v1/options/indicators/rsi/{ticker}

Example request

curl \
  "https://api.cutemarkets.com/v1/options/indicators/rsi/O:NFLX260402C00075000/?timespan=day&window=14&limit=10" \
  -H "Authorization: Bearer YOUR_API_KEY"

Sample response

{
  "results": {
    "values": [
      { "timestamp": 1775016000000, "value": 68.48397362973498 },
      { "timestamp": 1774929600000, "value": 66.67445148145187 },
      { "timestamp": 1774843200000, "value": 58.445579575082704 }
    ]
  },
  "status": "OK",
  "request_id": "cm_49c532b5d7ef43209fcf65f6aa74fb42"
}

Interpretation

RSI is bounded between 0 and 100, so it compares across contracts more cleanly than a raw moving average. A high value means recent gains have dominated recent losses inside the lookback window; a low value means recent losses have dominated. For options, the useful question is usually not "is RSI high?" but "is momentum consistent with the contract's spread, volume, expiration, and implied volatility context?"

RSI versus moving averages

RSI compresses momentum into a bounded oscillator. SMA and EMA return price-like values, so they are better for trend levels and crossovers. MACD compares two EMAs and adds a signal line. In a scanner, RSI is best used as one feature beside quote freshness, bid/ask width, open interest, and expiration distance.

curl \
  "https://api.cutemarkets.com/v1/options/chain/NFLX/?expiration_date=2026-04-17&limit=50" \
  -H "Authorization: Bearer YOUR_API_KEY"

Use the chain request to choose a liquid contract first, then request RSI for the selected OCC ticker. That order avoids calculating momentum on a contract that would fail the execution-quality gate.

Practical use in scanners

RSI is most useful after the contract universe has already been filtered. Start with listed expirations, choose candidate contracts from a chain, remove contracts with weak liquidity, then calculate RSI on the surviving OCC tickers. That ordering keeps the scanner from ranking contracts that look mathematically interesting but cannot be traded or audited.

For options, a high RSI can describe strong premium momentum, but premium momentum can come from several sources at once. The underlying may have moved, implied volatility may have expanded, time value may have compressed less than expected, or a sparse print may have moved the series. Pair RSI with quote freshness, bid/ask width, volume, open interest, delta, and expiration distance before using it as a decision feature.

Implementation checks

• Store the window, timespan, series_type, and adjusted flag with every RSI value.
• Confirm the contract has enough bars to support the requested lookback.
• Avoid comparing daily RSI against intraday RSI without a label.
• Reject or flag RSI values from contracts with stale quotes or very wide spreads.
• Review RSI beside the underlying move and implied-volatility context.

These checks make RSI useful as a repeatable feature rather than a chart-only decoration. They also help explain why two contracts with similar RSI values can still have very different risk and execution profiles.

RSI implementation notes

RSI is a derived stock indicator, so the artifact needs the source bar window before it needs the oscillator value. Store ticker, timespan, adjusted flag, window length, warm-up coverage, bar timestamp, and calculation timestamp. If a scanner uses RSI to select option candidates, carry those fields into Stock and Options Data Join Workflow before requesting expirations or chains.

Avoid treating oversold or overbought labels as trade evidence. A 30 RSI row can be a watchlist filter, but the option leg still needs expiration validation, chain context, quote freshness, bid/ask spread, and open interest checks. Pair this page with Options Contract Selection when an RSI stock screen becomes an options workflow.

Additional implementation review

Review the RSI indicator workflow as a sequence of named data objects, not as a single helper call. The implementation should preserve window length, source aggregate, adjusted close policy, timestamp, pagination cursor, warm-up period, and signal threshold. Those fields make support tickets, CI fixtures, and replay notebooks easier to compare because every step can point to the exact request and response that created the displayed value.

The main failure mode is that a dashboard can compare RSI values calculated from different bar sources or different adjustment policies. Before promoting the workflow, run one concrete example through discovery, retrieval, display, logging, and error handling. Keep the resulting artifact beside the code path so future changes can prove they still use the same terminology and the same market-data assumptions.