Choosing proxy IPs for crawlers: acceptance, concurrency, cost

Measure acceptance before you talk about scale

Do not open with a large bundle. Buy the minimum, run it against your real targets, and record the ratio of 200s to non-200s — and within the non-200s, how many are actual blocks.

Until you have that number, every cost estimate is fiction. The same proxy product can behave very differently on two targets, so somebody else’s numbers do not transfer.

Concurrency is set by the target, not by you

People treat concurrency as a knob they own. The ceiling is actually the target’s rate limit, and past it, more concurrency only raises failures while still burning traffic.

Ramp up gradually, watch the acceptance curve, find where it starts falling off, and step back one notch. That number is your real usable concurrency.

Where the traffic goes matters more than how much

Most crawler traffic is spent on images, video, fonts, and third-party analytics scripts you never parse.

Block them at the request layer and consumption drops sharply, taking the per-GB bill with it. If you drive a headless browser, resource interception rules are mandatory or costs run away from you.

• Block image, media, and font request types
• Cut third-party domains you do not need
• Hit the API instead of rendering the whole page where you can

Rotating or static depends on session needs

Independent, login-free collection is most flexible on rotating residential billed per GB. Anything holding a login, or binding one account to one exit, needs static residential.

And if the target ignores IP type entirely, try datacenter first — the same job can cost considerably less. Your acceptance test from step one is what tells you.

Get monitoring up before you scale

At minimum: acceptance rate per domain, failure distribution by status code, traffic per unit of work, and remaining balance on the proxy account.

Skip the last one and your job dies silently at 3am when the balance runs out, and you find out the next morning. NextProxy keeps usage, balance, orders, and expiry on one page for exactly this reason.