user52822: I am writing a trading bot and concerned about rate limits.
I need realtime notifications for change in price either like a PUSH api service.
Bitfinex appears to be the only major exchange that offers PUSH notifications, so I am not concerned with Bitfinex. But all other major exchanges such as Kraken are of concern.
How can I get realtime ticker data for the major bitcoin exchanges?

user52446: Poloniex has a PUSH API, check their API FAQ here: https://poloniex.com/support/api/
The other API requests they have said to have 6 request/sec rate limitation, which in my opinion is still pretty close to real-time if you update the Ticker this way.
Kraken does not provide PUSH API, from their FAQ it looks like a normal user (Tier 2) has a limitation on ticker of 1 request per 3 seconds (0.33 request/sec), but will be blocked for 15 minutes when exceeded.
Coinbase has only a PULL API with a 10,000 request per hour (2.7 request/sec) based on their Developer guide, although they operate a separate business called GDAX which has a WebSocket based real-time API.

52822: <p>I am writing a trading bot and concerned about rate limits.</p>

<p>I need realtime notifications for change in price either like a PUSH api service.</p>

<p>Bitfinex appears to be the only major exchange that offers PUSH notifications, so I am not concerned with Bitfinex. But all other major exchanges such as Kraken are of concern.</p>

<p>How can I get realtime ticker data for the major bitcoin exchanges?</p>
 52446: <p><a href="https://poloniex.com/" rel="nofollow noreferrer">Poloniex</a> has a PUSH API, check their API FAQ here: <a href="https://poloniex.com/support/api/" rel="nofollow noreferrer">https://poloniex.com/support/api/</a></p>

<p>The other API requests they have said to have <strong>6 request/sec</strong> <a href="https://github.com/BitBotFactory/poloniexlendingbot/issues/167" rel="nofollow noreferrer">rate limitation</a>, which in my opinion is still pretty close to real-time if you update the Ticker this way.</p>

<p><a href="https://kraken.com" rel="nofollow noreferrer">Kraken</a> does not provide PUSH API, from their <a href="https://www.kraken.com/help/api#api-call-rate-limit" rel="nofollow noreferrer">FAQ</a> it looks like a normal user (Tier 2) has a limitation on ticker of 1 request per 3 seconds (<strong>0.33 request/sec</strong>), but will be blocked for 15 minutes when exceeded.</p>

<p><a href="https://coinbase.com/" rel="nofollow noreferrer">Coinbase</a> has only a PULL API with a 10,000 request per hour (<strong>2.7 request/sec</strong>) based on their <a href="https://developers.coinbase.com/api/v2#rate-limiting" rel="nofollow noreferrer">Developer guide</a>, although they operate a separate business called <a href="https://gdax.com/" rel="nofollow noreferrer">GDAX</a> which has a <a href="https://docs.gdax.com/#websocket-feed" rel="nofollow noreferrer">WebSocket based real-time API</a>.</p>
