Sample LOG File Download — Any Size, Free

Log files are the first thing you reach for when something breaks in production, and the tooling that ingests them — Splunk, Datadog, Grafana Loki, the ELK stack — behaves very differently at a few kilobytes versus a few gigabytes. A generated log file at an exact target size lets you validate your ingestion pipeline, rotation rules, and parser performance before any real application error lands in it. Everything is generated in your browser; no log data leaves your machine.

Common use cases for Log File test files

Testing log aggregators (Splunk, Datadog, Loki) with realistic file sizes
Validating log rotation and archival rules before a real incident
Stress-testing log parsers and grok pattern matching at scale
Benchmarking log ingestion pipeline throughput

Related formats

Sample File Generator — all 20 formats, any exact size, free in-browser download.

Frequently asked questions

What log format does the generated file use?

Entries follow a common structured log pattern with an ISO 8601 timestamp, a log level (INFO, WARN, ERROR, DEBUG), a source identifier, and a realistic message. The format is close enough to Apache combined log, Nginx error log, and common application log patterns that most parsers ingest it without custom grok patterns.

Can I use this to test log rotation tools like logrotate?

Yes. The file is plain text with consistent line structure and realistic file sizes, which is exactly the input logrotate, fluentd, and similar agents expect when deciding whether to rotate.

Why would I generate a large log file instead of just waiting for my app to produce one?

Because you want to catch ingestion failures, memory overflows, and parser timeouts in a controlled environment before a real production incident generates a 100 MB log file and overwhelms your monitoring system.

Download a Sample LOG File (Any Size)