What is Success Rate?
Success rate is the share of requests through a proxy that return the content you asked for. Teams count clean 2xx responses carrying real page data as successes, and treat blocks, CAPTCHA pages, timeouts and connection resets as failures, including the ones that arrive with a 200 status. The figure varies enormously by destination, so one global number says little.
The hard part is classification, not counting. HTTP 403 and 429 are unambiguous refusals, while a 200 is not automatically a win, since challenge pages, consent walls and empty result sets all arrive with a success status. A scraper that inspects only the status code will report excellent numbers while collecting nothing usable. Below HTTP, count TCP resets, TLS handshake failures and timeouts as failures too. A 407 means the proxy rejected your credentials, which is a configuration fault rather than a target or network problem, so give it its own bucket.
Several things move the number, and IP type is only one of them. Rotation policy has a large effect, since rotating on every request breaks sites that expect a stable session, while holding one address through an aggressive crawl gets that address flagged. Header order and TLS fingerprint decide outcomes on destinations that fingerprint clients, independently of where the traffic comes from. Geographic consistency counts as well, because an account created in Germany that suddenly appears from a Brazilian mobile IP raises the risk score before the page even loads.
Quote two numbers instead of one. First-attempt success rate tells you how well the setup is tuned; success rate after retries tells you what the pipeline delivers. Vendors normally publish the second, which can look strong even when every third request needs two more attempts. Retries are not free under per-GB pricing, because a blocked response still carries a full TLS handshake and a block page, and those bytes are billed like any others. Track cost per successful record alongside the percentage.
Bucket the metric by destination domain, country and hour before drawing any conclusion from it. An aggregate across a dozen targets hides the single hardened site that is failing outright, which is usually the one you care about. Sample size deserves attention too, since a rate computed over a couple of hundred requests swings several points on noise alone. PROXIES.SX publishes 92% success on major platforms; like every vendor figure, it describes their test conditions, so measure against your own targets before committing volume.
Where you meet it
Success rate is the number your job runs on. It shows up when yesterday's crawl came back thin, or in a bug report saying the parser found no rows. The same number drives the decision about whether to change IP type or fix your request headers. Classify each failure at the moment it happens and store the reason with the record. A bare percentage tells you something is wrong without telling you which of those two repairs to make.
Common questions
What counts as a failed request?
Anything that does not return the content you asked for: explicit blocks such as 403 and 429, CAPTCHA or interstitial pages served with a 200, timeouts, TCP resets, gateway 502 and 504 responses, and truncated or empty payloads. Proxy authentication errors are normally tracked apart, since they indicate a configuration problem rather than a block.
Why is my success rate lower than a provider advertises?
Vendor figures come from their own targets, rotation settings, concurrency and request timing. On many sites, TLS fingerprint, header order, geographic matching and request rate move the outcome more than the IP source does. Compare providers by running your own code path against your own destinations at the same time of day.
What is a good success rate for mobile proxies?
It depends entirely on the destination. Lightly protected sites sit in the high nineties for most setups, while platforms with device fingerprinting and behavioural scoring run far lower for everyone. Benchmark against the same target, same code and same hour rather than against a general industry figure.
Related terms
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