Databay field notes
Proxy guides, experiments & operator notes
Engineering guides and first-party measurements for people operating proxy-backed data systems.
- 01Guides20
- 02Tutorials13
- 03Comparisons5
- 04Research5
Newest update Aug 09, 2026 · methodology-open research
Ad Verification With Proxies: A Controlled QA Workflow
Run authorized ad verification with proxies using platform previews, one controlled regional variable, a reviewable record, and clear stop conditions.
11 min readRead articleTutorials
13 entries
Checking the Proxy and the Firewall: Fix the Chrome Error
Chrome shows this when a configured proxy fails. Find whether a proxy is set, remove leftovers you never wanted, and fix the one you...
10 min readRead
curl Error 7 and 56: Exit Codes Explained and Fixed
curl exit code 7 is a connection failure, not a timeout. What codes 6, 7, 28 and 56 each prove about a request, and how to fix each.
12 min readRead
ECONNREFUSED: Meaning, the localhost Trap, and Fixes
ECONNREFUSED means a reachable machine answered no. Read the address and port fields, rule out the localhost dual-stack trap, then fix...
11 min readRead
ERR_CONNECTION_REFUSED: What It Means and How to Fix It
ERR_CONNECTION_REFUSED means the server answered no, instantly. What refusal tells you, the localhost case, and ranked fixes for each side.
10 min readRead
ERR_CONNECTION_RESET: What It Means and How to Fix It
ERR_CONNECTION_RESET means the connection opened and was then killed by a TCP reset. How to tell who sent it, and the fix that follows.
12 min readRead
ERR_CONNECTION_TIMED_OUT: What It Is and How to Fix It
ERR_CONNECTION_TIMED_OUT means pure silence before the browser gave up. How silence differs from refusal and the fixes that match each...
10 min readRead
ERR_NAME_NOT_RESOLVED: What It Means and How to Fix It
ERR_NAME_NOT_RESOLVED means DNS returned no address, so your browser never connected. Two commands that localize it, then the fixes that...
12 min readRead
ERR_TOO_MANY_REDIRECTS: How to Break a Redirect Loop
The browser gave up on a redirect loop. Fix it as a visitor in two minutes, see the loop with curl, and repair the server rules causing it.
10 min readRead
ERR_TUNNEL_CONNECTION_FAILED: Causes and How to Fix It
ERR_TUNNEL_CONNECTION_FAILED means a proxy would not open the CONNECT tunnel HTTPS needs. What a tunnel is, and fixes ranked by the real...
12 min readRead
How to Test a Free Proxy Safely
Use unknown public proxies only for disposable, non-sensitive diagnostics against systems you are authorized to test.
3 min readRead
How to Use Proxies for Ecommerce Price Monitoring
Learn how to use proxies for ecommerce price monitoring: choose an authorized source, normalize offers, vary one network signal, and...
12 min readRead
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