# Learn How to Lower Heroku Dyno Latency through Persistent Connections (Keep-alive)

DevFeed: [Learn How to Lower Heroku Dyno Latency through Persistent Connections (Keep-alive)](<https://devfeed.tech/articles/learn-how-to-lower-heroku-dyno-latency-through-persistent-connections-keep-alive-26462.md>)

Original publisher: [Read original article](<https://www.heroku.com/blog/learn-how-to-lower-heroku-dyno-latency-keep-alive/>)

Author: Richard Schneeman

Published: 2025-11-04T16:27:37Z

Content type: tutorial

Language: en

Sources: [Heroku](<https://devfeed.tech/sources/heroku.md>)

Topics: [Heroku](<https://devfeed.tech/topics/heroku.md>), [Latency](<https://devfeed.tech/topics/latency.md>), [Persistence](<https://devfeed.tech/topics/persistence.md>), [web applications](<https://devfeed.tech/topics/web-applications.md>), [HTTP](<https://devfeed.tech/topics/http.md>), [networking](<https://devfeed.tech/topics/networking.md>)

Tags: [engineering](<https://devfeed.tech/tags/engineering.md>), [heroku](<https://devfeed.tech/tags/heroku.md>), [how-to](<https://devfeed.tech/tags/how-to.md>), [http](<https://devfeed.tech/tags/http.md>), [latency](<https://devfeed.tech/tags/latency.md>), [networking](<https://devfeed.tech/tags/networking.md>), [performance](<https://devfeed.tech/tags/performance.md>), [performance-optimization](<https://devfeed.tech/tags/performance-optimization.md>), [persistence](<https://devfeed.tech/tags/persistence.md>), [web-applications](<https://devfeed.tech/tags/web-applications.md>)

## AI overview

This tutorial explains how persistent keep-alive connections can reduce Heroku dyno latency by amortizing the overhead of new TCP connections and avoiding TCP slow start for later requests. It introduces the relationship between HTTP requests, TCP connections, and web server behavior.

## Source excerpt

The Performance Penalty of Repeated Connections Before the latest improvements to the Heroku Router, every connection between the router and your application dyno risked incurring the latency penalty of a TCP slow start. To understand why this is a performance bottleneck for modern web applications, we must look at the fundamentals of the Transmission Control [...] The post Learn How to Lower Heroku Dyno Latency through Persistent Connections (Keep-alive) appeared first on Heroku.