# RSI (Relative Strength Index) Calculator

> RSI (Relative Strength Index) Calculator is a paid API for AI agents from agent402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-16).

Computes the Relative Strength Index (RSI) using Wilder's smoothing over a supplied price series, returning one value per input position (null until the first full period).

## Facts

- Endpoint: POST https://agent402.tools/api/rsi?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/rsi-relative-strength-index-calculator-503f8dd2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QwH8E6qpzPpGToHSURqU1

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability rsi-relative-strength-index-calculator-503f8dd2 -d '<json body>'
```

Example prompt: Calculate the RSI with a 14-period look-back on these daily closing prices (oldest first): [44.34, 44.09, 44.15, 43.61, 44.33, 44.83, 45.10, 45.15, 43.61, 44.33, 44.83, 45.10, 45.15, 43.61, 44.33] and tell me if the asset looks overbought or oversold.

## When to prefer this

Choose this endpoint when you need a standards-compliant RSI using Wilder's smoothing (not simple moving average) and want to supply your own price series rather than fetching it from a data provider. Ideal for backtesting pipelines, trading signal generation, or on-the-fly technical analysis where you already have the price data in hand. Prefer this over bundled research skills when you only need the RSI computation itself without additional API calls.

## Known failure modes

- Fewer than period+1 values supplied — returns error or all nulls
- Period outside the allowed range of 2–200 — validation error
- More than 10,000 values submitted — request rejected
- Non-numeric values in the price series — parsing or validation error
- Payment not provided or invalid — 402 Payment Required

## How this service works

Compute the relative strength index (Wilder's smoothing, default period 14) over a price series you supply, such as daily closes. Returns one value per input position (null until the first full period), the latest value, and a reading: overbought at 70 or above, oversold at 30 or below, else neutral. No market data is fetched: pass your own closes.

## Output

An array of RSI values (one per input price), where the first (period - 1) entries are null (warm-up period), followed by floating-point RSI values between 0 and 100 computed using Wilder's exponential smoothing method.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "period": {
   "type": "number",
   "description": "Look-back period, 2 to 200 (default 14)"
  },
  "values": {
   "type": "array",
   "description": "Price series, oldest first (closes), at least period + 1 values, max 10000"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "rsi": [
   null,
   null,
   null,
   null,
   null,
   null,
   null,
   null,
   null,
   null,
   null,
   null,
   null,
   null,
   70.4641,
   66.2496,
   66.4809,
   69.3469,
   66.2947,
   57.915
  ],
  "count": 20,
  "latest": 57.915,
  "period": 14,
  "reading": "neutral"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rsi-relative-strength-index-calculator-503f8dd2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.tools](https://www.zero.xyz/host/agent402.tools/llms.txt)