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Sticky Session & Concurrency Loss · Updated 2026

Your proxy bill is not GB bought. It is GB burned on flows that died mid-checkout.

A residential IP that disappears halfway through a login or checkout invalidates the cf_clearance token bound to it, so every completed step has to be replayed from zero on a new IP. Sticker price per GB hides that tax. Enter your workload and see the re-run loss rate, the real GB you burn, and what it costs per month — sticky sessions versus forced per-request rotation.

Monthly ledger

Same 40-concurrency workload, same target sites, two IP strategies.

① Sticky session

IP held for the full flow • default 10 min window

$—

cf_clearance re-run loss rate—
Step executions per flow—
Real traffic per flow—
Real consumed traffic / month—
Completed flows / month—
Cost per completed flow—

② Per-request rotation

New IP every request • clearance never survives a step

$—

Challenge re-run loss rate—
Step executions per flow—
Real traffic per flow—
Real consumed traffic / month—
Completed flows / month—
Cost per completed flow—

Sticky session saves —

Adjust the inputs to see how much the re-run tax costs you each month.

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What is being calculated

expected step runs = steps ÷ (1 − drop) — with a drop probability drop per flow, a flow needs a geometric number of attempts; only the last one completes.
re-run loss rate = drop ÷ (1 − drop) — the share of step executions that are pure waste because the sticky IP died and the cf_clearance cookie no longer matches the new exit IP.
real traffic per flow = steps ÷ (1 − drop) × payload — the vendor meters every byte, including the bytes inside a flow that never finished.
monthly attempts = concurrency × (active minutes ÷ duration) × 30 and monthly GB = monthly attempts × real traffic per flow.
Per-request rotation is modelled with the same geometric form, but the hazard is the per-request challenge failure rate rather than an IP drop, because a rotating IP can never carry a clearance token to the next step.

Same math, four mirrors: GPU TCO Space • RAG scraping TCO Space • this proxy Space • payments Space. Full sites: scrape • gpu • proxy • pay