# Concurrent connections

Concurrent connections, often called threads in proxy marketing, are the number of simultaneous connections a customer may keep open through a proxy service. Some providers cap them per plan; others, ProxShift included, leave them unlimited and bill only traffic or addresses. The practical limit is then the target's tolerance and the size of the pool in the location you use.


## What concurrency buys

Throughput. A crawler that waits 800 ms per page collects 75 pages a minute on one connection and 7,500 on a hundred. On a rotating pool each connection is also a different exit, so concurrency and rotation grow together.


## Where the real ceilings are

- The target: per-domain politeness matters more than the proxy's limits.
- The pool: 500 concurrent Berlin sessions need 500 Berlin households online at that moment.
- Your client: open file descriptors, DNS, and connection pools are usually exhausted before the proxy is.


## How it works at ProxShift

ProxShift sets no limit on concurrent connections or sessions on any network; residential and mobile are billed per GB, dedicated addresses per IP.

Source: https://proxshift.com/glossary/concurrent-connections