Thread
A thread is one simultaneous request. Proxy Compare records a concurrency figure on 7 of the 545 plans it prices, read 5 Oct 2026. Providers sell threads, ports and concurrent connections as though they were different products; they are the same constraint, and almost none of them publish the number.
Why it costs you money
It sets your ceiling on how fast you can work, no matter how much traffic you bought. It is also where unlimited plans hide the meter: several providers sell uncapped gigabytes and then price the thread count, so the resource you run out of is concurrency rather than data.
See it in the data
Related terms
- Concurrency limitThe cap on how many requests you can have in flight at once. Often the real constraint on a scraping job, not price.
- Success rateThe share of requests that get through. The number that decides everything, and the one no comparison table can give you.
- Ports vs IPsA numbered endpoint you connect to. On some providers a port is the billing unit, and it is not the same as an address.
- Per-GB pricingBilling by the gigabyte you move, the dominant model for residential proxies and the one most comparisons assume.
- Every term we define
Questions
How many threads do I need?
As many as you want requests in flight at once, which is not the same as how many requests you make in total. 7 of the 545 plans priced here publish a concurrency figure at all, read 5 Oct 2026.
Are threads, ports and concurrent connections the same thing?
They are one constraint counted three ways. The naming differs by vendor rather than by mechanism, and that is a large part of why plans are hard to compare on anything but price.
What happens if I go over?
It varies and is rarely documented: some providers 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 Because the limit itself is usually unpublished, the behaviour past it almost always is too.