How do you evaluate proxy providers?

I'm curious: how do you evaluate and compare proxy providers?

Inside the ScrapeOps Proxy Aggregator, we've integrated around 50 proxy providers into a single tool. We continuously test and benchmark them to determine which providers offer the best performance at the lowest cost for different target websites.

The main performance metric we've settled on is average success latency:

How quickly does a provider return a successful response?

Success rate or latency alone doesn't tell the full story.

A provider might respond quickly but have a low success rate. Another might eventually succeed, but take 30 or 60 seconds to return each response. Even if its success rate looks reasonable, those slow responses can clog up your scraping pipeline and significantly reduce throughput.

Average success latency brings these factors together. It helps us measure how much successful throughput we can send through a provider, how reliably it performs over time, and how much that successful traffic actually costs.

We then combine this with pricing to calculate metrics such as the cost per successful request or per million successful requests. This gives us a more realistic comparison than simply looking at advertised prices or raw success rates.

That's how we evaluate providers, but I'd love to hear how others approach it:

• Which metrics matter most to you?

• Do you prioritize success rate, latency, reliability, or cost?

• Do you run your own tests or rely on reviews and public benchmarks?

• Have you found any particular metric to be the best predictor of real-world performance?