Concurrency limit
A concurrency limit caps how many requests you can have in flight at once. Proxy Compare records one on 7 of the 545 plans it prices, read 5 Oct 2026. Almost nobody publishes it, so we record the silence rather than an estimate, and it is often the real constraint on a job.
Why it costs you money
This is frequently the binding constraint rather than price. A plan with cheap bandwidth and a low concurrency cap can take days to finish a job that a dearer plan finishes in an hour, and the cap is usually further down the pricing page than the headline rate.
See it in the data
Related terms
- Bandwidth overageWhat a provider charges once you pass the gigabytes your plan includes. Often several times the headline rate.
- Sub-userA separate set of credentials under one account, so you can split traffic by project, client or machine.
- ThreadOne simultaneous connection. On unlimited-bandwidth plans, threads are usually the resource being sold instead of gigabytes.
- Session durationHow long a provider will keep giving you the same address before it rotates, measured in minutes or requests.
- Credit (scraping API)Scraping APIs bill in credits, and one credit buys different amounts of work depending on the request. What each provider charges, with sources.
- Every term we define
Questions
How many plans here publish a concurrency limit?
7 of the 545 plans Proxy Compare prices, read 5 Oct 2026. Almost no provider puts it in published pricing, so we record the silence rather than an estimate.
Is a thread the same as a concurrent connection?
Yes, for anything you are buying on. Providers sell threads, ports and concurrent connections as though they were different products; they are the same constraint counted three ways, which is why comparing them across vendors is harder than comparing a price.
What happens when I go over the limit?
It varies by provider and is rarely documented: some queue the request, some return an error, some throttle the whole account. Because the limit itself is usually unpublished, the behaviour past it almost always is too.