Error Pattern Checker

Validators and utilities that complement Error Pattern Checker — same session, no sign-up.

Find log lines that match a pattern: plain text or regex. Get matching lines with line numbers.

About this tool

Paste log or text, enter a pattern (plain substring or regular expression). Matching lines are listed with line numbers. Use "Regex" for regular expressions; "Case sensitive" for exact case match.

For full log management, use a dedicated service.

How to use this tool

  1. Paste your sample in the input (or fetch from URL if this tool supports it).
  2. Run the main action on the page to execute Error Pattern Checker.
  3. Read the result, fix the source data or config, and re-run if needed.

What this check helps you catch

  • Find log lines that match a pattern: plain text or regex. Get matching lines with line numbers.
  • Limits called out in the description (what this tool does not verify — e.g. live network reachability, issuer databases, or strict schema contracts unless stated).
  • Structural or syntax mistakes that would break parsers, serializers, or the next step in your workflow.

FAQ

What does Error Pattern Checker do?
Find log lines that match a pattern: plain text or regex. Get matching lines with line numbers. Use the form above, then see “How to use” and “What this check helps you catch” for behavior detail.
Is this a substitute for server-side validation?
No. Use it for manual checks and triage; production systems should still validate and authorize on the server.
Where does processing happen?
Most validators here run in your browser. If a tool calls an API, that is stated on the page. See the site privacy policy for data handling.