Why your scraper keeps getting blocked

When a scraper starts getting blocked, the instinct is to fight the block: rotate proxies harder, spoof more headers, find a service that promises to defeat detection. That is an arms race you will lose, and it usually misses the point. Sites do not block scraping in the abstract; they block behavior that looks abusive. Fix the behavior and most blocks evaporate on their own. Here is what actually triggers them.

You are going too fast

The number one cause, by a wide margin. A burst of requests far faster than a human could browse is the clearest possible signal of an automated client, and rate-based blocking is the cheapest defense a site can run. Cap your request rate, add random jitter so your timing is not robotically even, and you stop tripping the simplest and most common trap there is.

You look anonymous and evasive

A missing or generic User-Agent, no referer, headers that do not match any real browser, these read as “something trying to hide.” Counterintuitively, an honest, identifiable client that says who it is gets blocked far less than one that tries to look like nothing. If you are collecting public data politely, you have no reason to hide, and hiding is itself a flag.

You ignore the signals you are given

Sites tell you what they want. robots.txt lists what not to touch. A 429 or 503 asks you to slow down. A Retry-After header says exactly how long to wait. Scrapers that barrel through these get escalated from a soft throttle to a hard ban quickly. Honoring them, backing off on a 429, waiting the Retry-After, is what keeps you on the soft side of the line.

You re-fetch everything, constantly

Pulling the same unchanged pages over and over multiplies your footprint for no data. Cache what you have, use conditional requests (If-Modified-Since, ETag), and only re-fetch what actually changed. A scraper with a good cache is a fraction of the load and a fraction of the suspicion.

You hammer at the worst possible time

Running a heavy job during the target’s peak traffic makes your load both more noticeable and more harmful. Schedule for off-peak hours. The same volume of requests that gets flagged at noon often passes unnoticed at 3 a.m. in the site’s timezone.

The honest take on proxies

Proxy rotation has legitimate uses, distributing genuinely high-volume collection of public data, or reaching geo-specific content. But using proxies to evade a rate limit you should be respecting just resets the same fight from a new address, and it is what turns a temporary throttle into a permanent block. Rotate to distribute polite load, not to out-stubborn a server that is asking you to stop.

The plug

SnowScrape bakes the good-citizen defaults in, rate limiting, scheduling, and proxy rotation used the right way, so your jobs keep completing instead of getting your address blocklisted. If you would rather collect public data reliably than run an arms race, it is at scrape.snowforge.dev.