- Cost
- Free
- Sign-up
- None
- Runs
- In your browser
Error log viewer
Turn a server error log into something legible: grouped traces, repeat offenders, and the errors quietly firing on every single request.
What it does
4 capabilities
- Grouping
- Identical errors collapse into one entry with a count, so a log with ten thousand lines and four real problems reads as four real problems.
- Stack traces
- Multi-line PHP and Apache traces are kept together rather than shredded into separate rows, which is what makes most log tooling useless here.
- Severity filtering
- Separate the fatals from the notices, and see what is actually breaking versus what is merely noisy.
- Frequency
- Sort by how often something fires. The error nobody reported is usually the one at the top.
How it runs
- Step 1
Load a PHP, Apache or generic server error log from your machine. It stays on your machine.
- Step 2
Group and filter by severity or frequency until the real failures separate from the noise.
- Step 3
Read the trace in place, then close the tab.
Accepted input
PHP and Apache
- PHP error logs
- PHP fatal errors and warnings
- Multi-line stack traces
- Apache error logs
Generic
- Timestamped plain-text logs
- Severity-prefixed lines
- Custom delimited formats
How to read a server error log
Anatomy of a PHP error line
[12-Oct-2026 06:25:14 Europe/Vienna] PHP Warning: Undefined array key "id_lang" in /var/www/shop/classes/Product.php on line 412Timestamp, severity, message, file and line. A fatal error is usually followed by a stack trace on the next lines, numbered from #0. Read it from the top: the first frame is where it failed, the frames below are how execution got there.
Severity: what to fix first
Fatal errors and parse errors stop the request: the visitor gets a blank page or a 500. Warnings let the request finish but often mean wrong output - missing data, a broken price, an empty list.
Notices and deprecation messages rarely break anything today. Deprecations are, however, the list of what will break on the next PHP upgrade, so clear them before you schedule one.
Apache and Nginx error logs
Apache error lines carry the module and level in brackets, such as [php:error] or [core:error], plus the client IP. Codes prefixed with AH - AH01630, client denied by server configuration, for example - are searchable and usually name the exact directive involved.
Nginx writes [error] or [crit] followed by the worker process id. Lines like upstream timed out or connect() failed usually mean PHP-FPM or the application behind Nginx is slow or down, not Nginx itself.
Find the error that fires on every request
The loudest error is rarely the important one. The important one is often a quiet warning repeated thousands of times - in a template, or a module hook that runs on every page view. Grouped by message and sorted by count, it rises to the top. Fixing it removes thousands of lines at once and often takes time off every response.
Error logs and SEO
Search engines never read your error log, but they see its effects: 500 responses during a crawl, pages that time out, templates that render without their content when a warning breaks a loop. If Search Console reports server errors or a drop in crawled pages, the error log for the same hours is where the cause is written down. Line the timestamps up against the access log to see which URLs were hit.
FAQ
- How is this different from the access log viewer?
- An error log records what broke - PHP fatals, warnings, Apache errors - and this viewer groups those by trace so the repeat offenders stand out. An access log records every request: who asked for which URL and which status they got. For traffic, crawler and status-code analysis, use the access log viewer.
- Can I open IIS or proxy logs here?
- IIS W3C logs and proxy logs such as ISA, Forefront TMG or Squid record requests, not errors - they are access logs. Open them in the access log viewer, which detects those formats automatically.
Nothing is uploaded. Nothing is stored.
It runs entirely in your browser, with no account and no server round-trip. Close the tab and it is gone.