Log file language preview

1. A basic application log

ISO timestamps, levels, tags, and a stack trace

horizon-dark

2026-09-06T10:00:00.123Z INFO  [main] Starting server on 127.0.0.1:8080
2026-09-06T10:00:01.456Z WARN  [req-123] slow query id=42 duration=1200
2026-09-06T10:00:02.789Z ERROR [worker-1] Exception: NullPointerException
    at com.foo.Bar.process(Bar.java:10)
2026-09-06T10:00:03.012Z DEBUG [main] pid[4821] GET /api/users 200

atom-one-dark

2026-09-06T10:00:00.123Z INFO  [main] Starting server on 127.0.0.1:8080
2026-09-06T10:00:01.456Z WARN  [req-123] slow query id=42 duration=1200
2026-09-06T10:00:02.789Z ERROR [worker-1] Exception: NullPointerException
    at com.foo.Bar.process(Bar.java:10)
2026-09-06T10:00:03.012Z DEBUG [main] pid[4821] GET /api/users 200

github-dark

2026-09-06T10:00:00.123Z INFO  [main] Starting server on 127.0.0.1:8080
2026-09-06T10:00:01.456Z WARN  [req-123] slow query id=42 duration=1200
2026-09-06T10:00:02.789Z ERROR [worker-1] Exception: NullPointerException
    at com.foo.Bar.process(Bar.java:10)
2026-09-06T10:00:03.012Z DEBUG [main] pid[4821] GET /api/users 200

dracula

2026-09-06T10:00:00.123Z INFO  [main] Starting server on 127.0.0.1:8080
2026-09-06T10:00:01.456Z WARN  [req-123] slow query id=42 duration=1200
2026-09-06T10:00:02.789Z ERROR [worker-1] Exception: NullPointerException
    at com.foo.Bar.process(Bar.java:10)
2026-09-06T10:00:03.012Z DEBUG [main] pid[4821] GET /api/users 200

nord

2026-09-06T10:00:00.123Z INFO  [main] Starting server on 127.0.0.1:8080
2026-09-06T10:00:01.456Z WARN  [req-123] slow query id=42 duration=1200
2026-09-06T10:00:02.789Z ERROR [worker-1] Exception: NullPointerException
    at com.foo.Bar.process(Bar.java:10)
2026-09-06T10:00:03.012Z DEBUG [main] pid[4821] GET /api/users 200

github

2026-09-06T10:00:00.123Z INFO  [main] Starting server on 127.0.0.1:8080
2026-09-06T10:00:01.456Z WARN  [req-123] slow query id=42 duration=1200
2026-09-06T10:00:02.789Z ERROR [worker-1] Exception: NullPointerException
    at com.foo.Bar.process(Bar.java:10)
2026-09-06T10:00:03.012Z DEBUG [main] pid[4821] GET /api/users 200

2. Syslog and Apache formats

syslog-style and Apache combined log timestamps

horizon-dark

Sep  6 10:00:00 web1 sshd[1234]: Accepted publickey for admin
[06/Sep/2026:10:00:00 +0000] "GET /index.html HTTP/1.1" 200 512

atom-one-dark

Sep  6 10:00:00 web1 sshd[1234]: Accepted publickey for admin
[06/Sep/2026:10:00:00 +0000] "GET /index.html HTTP/1.1" 200 512

github-dark

Sep  6 10:00:00 web1 sshd[1234]: Accepted publickey for admin
[06/Sep/2026:10:00:00 +0000] "GET /index.html HTTP/1.1" 200 512

dracula

Sep  6 10:00:00 web1 sshd[1234]: Accepted publickey for admin
[06/Sep/2026:10:00:00 +0000] "GET /index.html HTTP/1.1" 200 512

nord

Sep  6 10:00:00 web1 sshd[1234]: Accepted publickey for admin
[06/Sep/2026:10:00:00 +0000] "GET /index.html HTTP/1.1" 200 512

github

Sep  6 10:00:00 web1 sshd[1234]: Accepted publickey for admin
[06/Sep/2026:10:00:00 +0000] "GET /index.html HTTP/1.1" 200 512

3. Structured key=value logs

key=value pairs and a UUID request id

horizon-dark

level=info msg="request completed" method=POST path=/api/orders status=201 duration_ms=42 request_id=550e8400-e29b-41d4-a716-446655440000

atom-one-dark

level=info msg="request completed" method=POST path=/api/orders status=201 duration_ms=42 request_id=550e8400-e29b-41d4-a716-446655440000

github-dark

level=info msg="request completed" method=POST path=/api/orders status=201 duration_ms=42 request_id=550e8400-e29b-41d4-a716-446655440000

dracula

level=info msg="request completed" method=POST path=/api/orders status=201 duration_ms=42 request_id=550e8400-e29b-41d4-a716-446655440000

nord

level=info msg="request completed" method=POST path=/api/orders status=201 duration_ms=42 request_id=550e8400-e29b-41d4-a716-446655440000

github

level=info msg="request completed" method=POST path=/api/orders status=201 duration_ms=42 request_id=550e8400-e29b-41d4-a716-446655440000