Signals

RSI — Relative Strength Index

Measure momentum on a 0 to 100 overbought/oversold scale.

What it is

RSI is a momentum oscillator on a 0 to 100 scale. Higher readings suggest strong recent buying pressure; lower readings suggest strong recent selling pressure.

When to use it

Flagging overbought and oversold conditions with thresholds like 70 and 30.
Pairing with trend filters so you only buy pullbacks in established uptrends.
Creating mean-reversion rules for research or alerts.

The maths

RS = avg_gain(N) / avg_loss(N), RSI = 100 - (100 / (1 + RS)) Values range from 0 to 100; the default N is 14.

What it tells you

Above 70 is conventionally overbought; below 30 is oversold. Divergences between RSI and price can signal reversals. Trend traders often use 40/60 as the neutral zone.

REST example

python

import os
import requests

response = requests.get(
  'https://api.financedata.com/v1/signals/RSI/AAPL',
  params={'start_date': '2025-01-01', 'end_date': '2025-04-30', 'period': 14},
  headers={'X-API-Key': os.environ['FDA_KEY']},
  timeout=30,
)
response.raise_for_status()
print(response.json())

MCP example

Tool call body

{
"name": "get_rsi",
"arguments": {
  "symbol": "AAPL",
  "start_date": "2025-01-01",
  "end_date": "2025-04-30",
  "period": 14
}
}

Agent prompt that triggers it

Check AAPL RSI across the first four months of 2025 and tell me whether the latest reading looks stretched.