GET/indicator/acos

Arc Cosine

Category: Math · Updated November 2026

The TAAPI.IO Arc Cosine API returns real-time and historical values for the Arc Cosine math function as JSON, for crypto pairs and US stocks. Send an exchange, symbol and timeframe to get real-time or historical data, with no candles to download and no calculations to maintain.

Spec	Value
Endpoint	`GET https://v2.taapi.io/indicator/acos`
Outputs	`value`
Markets	Binance, Binance Futures, Bybit, Gate.io, Kraken and US stocks
Timeframes	`1m` to `1w`
Delivery	REST, bulk and WebSocket

Get Arc Cosine with one API call

This request returns Arc Cosine for BTCUSDT on 1-hour Binance candles. Add your API key to run it here.

curl -G https://v2.taapi.io/indicator/acos \
  -H "Authorization: Bearer YOUR_API_KEY" \
  --data-urlencode "exchange=binance" \
  --data-urlencode "symbol=BTCUSDT" \
  --data-urlencode "timeframe=1h"

import requests

resp = requests.get(
    'https://v2.taapi.io/indicator/acos',
    headers={'Authorization': 'Bearer YOUR_API_KEY'},
    params={'exchange': 'binance', 'symbol': 'BTCUSDT', 'timeframe': '1h'},
)
print(resp.json())

const params = new URLSearchParams({"exchange": "binance", "symbol": "BTCUSDT", "timeframe": "1h"});
const res = await fetch(`https://v2.taapi.io/indicator/acos?${params}`, {
  headers: { Authorization: 'Bearer YOUR_API_KEY' },
});
console.log(await res.json());

Arc Cosine API response

This response came from the live API on 9 November 2026. Long lists are shortened here.

200 OK

{
  "value": [null],
  "timestamp": [1794218400]
}

This response can be null or empty when there is nothing to report for the requested candles, so handle that case in your code.

Field	Type	Description
`value`	array	Arc Cosine result
`timestamp`	integer[]	Unix time of each candle, in seconds

Arc Cosine API parameters

Name	Type	Required	Default	Description
`exchange`	string	Yes	—	`binance`, `binancefutures`, `bybit`, `gateio`, `kraken` or `stocks`
`symbol`	string	Yes	—	Pair or ticker, e.g. `BTCUSDT` or `AAPL`
`timeframe`	string	Yes	—	`1m` `5m` `15m` `1h` `4h` `1d` `1w`
`results`	integer	No	1	Number of values to return, or `max`
`backtrack`	integer	No	0	Candles to skip from the most recent

What is Arc Cosine?

Arc Cosine is a math function that returns the angle whose cosine is x. On TAAPI.IO it runs on the candles you request, so you can get the result without doing the calculation on your side.

Arc Cosine formula

Output	Calculation
Output	arccos(x)

How to read Arc Cosine in your code

Signal	Meaning	Condition
Result	Function output for the candle	`value`

Limitations: The input must be between −1 and 1. Prices are usually outside that range, so the API returns null for them. Nothing on this page is financial advice.

Read Arc Cosine from Python

Use backtrack=1 to read the result as of the last closed candle.

curl -G https://v2.taapi.io/indicator/acos \
  -H "Authorization: Bearer YOUR_API_KEY" \
  --data-urlencode "exchange=binance" \
  --data-urlencode "symbol=BTCUSDT" \
  --data-urlencode "timeframe=1h" \
  --data-urlencode "backtrack=1"

import requests

resp = requests.get(
    'https://v2.taapi.io/indicator/acos',
    headers={'Authorization': 'Bearer YOUR_API_KEY'},
    params={'exchange': 'binance', 'symbol': 'BTCUSDT', 'timeframe': '1h', 'backtrack': 1},
)
data = resp.json()
print(data['value'])

Get historical Arc Cosine values

Add results to return a series for backtesting or charting. The last element is the most recent candle.

curl -G https://v2.taapi.io/indicator/acos \
  -H "Authorization: Bearer YOUR_API_KEY" \
  --data-urlencode "exchange=binance" \
  --data-urlencode "symbol=BTCUSDT" \
  --data-urlencode "timeframe=1h" \
  --data-urlencode "results=100"

Get Arc Cosine for multiple symbols

Combine Arc Cosine with other indicators in one request. Each exchange, symbol and timeframe combination is one construct: Basic allows 1 per request, Pro 3 and Expert 10.

POST/bulk

curl -X POST https://v2.taapi.io/bulk \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "constructs": [
    {
      "id": "btc_1h",
      "exchange": "binance",
      "symbol": "BTCUSDT",
      "timeframe": "1h",
      "indicators": [
        {
          "id": "acos",
          "indicator": "acos"
        },
        {
          "id": "rsi",
          "indicator": "rsi"
        }
      ]
    }
  ]
}'

Stream Arc Cosine in real time

Subscribe over WebSocket to receive new values every 5 seconds while the candle is forming. Streaming supports 1m, 5m, 15m and 1h, and uses interval where REST uses timeframe.

WSSwss://v2.taapi.io/streaming

{
  "type": "subscribe",
  "id": "acos",
  "exchange": "binance",
  "symbol": "BTCUSDT",
  "interval": "1m",
  "indicator": "acos"
}

Arc Cosine API FAQ

What does the Arc Cosine API return?

It returns value, plus a timestamp for the request. Results are JSON.

Is the latest Arc Cosine value final?

No. The newest value belongs to the candle still forming and can change until it closes. Add backtrack=1 to read the last closed candle.

Can I get Arc Cosine for US stocks?

Yes. Use exchange=stocks with a ticker such as AAPL. US stocks are included on the Pro plan and above.

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