Can I paste multiple log lines at once?

Yes. The tool processes each line independently. Paste as many lines as you need and they will all be formatted.

Does it work with non-JSON logs?

The tool is designed for JSON-structured logs. Plain text logs are displayed as-is without additional formatting.

Can I filter logs by severity level?

Yes. You can filter by common log levels like error, warn, info, and debug to focus on the entries that matter most.

How to Read JSON Logs

3 min readDeveloper

Modern applications output structured logs in JSON format, but raw JSON log lines are dense and hard to read. This guide shows you how to pretty-print and parse JSON logs into a readable format using a free browser tool.

Quick Steps

1
Open Log Prettifier
Go to the Log Prettifier on Toolin.
2
Paste log lines
Enter raw JSON log lines.
3
View formatted logs
Read the prettified, highlighted output.
4
Search and filter
Find specific entries by level, message, or field.

Log Prettifier

Format and colorize server logs

Open Tool

Step-by-Step: Pretty-Print JSON Logs

Open the Log Prettifier tool

Navigate to the Log Prettifier on Toolin.

Paste your log lines

Paste one or more JSON log lines into the input area. Each line is treated as a separate log entry.

View the formatted output

The tool parses each line and displays the fields in a readable, formatted layout with syntax highlighting.

Filter or search

Use the search or filter options to find specific log entries or fields.

Working with Structured Logs

JSON logging is the standard for cloud-native applications. Tools like Winston, Bunyan, Pino, and structured logging libraries output one JSON object per line. Each line contains fields like timestamp, level, message, and contextual metadata. While this format is excellent for log aggregation systems, it is nearly impossible to read in raw form. The Log Prettifier transforms these dense lines into an organized, readable view.

Tips for Debugging with Logs

Filter by log level (error, warn, info) to focus on issues.
Look at timestamps to understand the sequence of events.
Check contextual fields like request IDs to trace a single request.
Compare log entries before and after a failure to identify the trigger.
Use the search function to find entries containing specific error messages.

Try Log Prettifier Now — Free, No Sign-up

Frequently Asked Questions

Can I paste multiple log lines at once?: Yes. The tool processes each line independently. Paste as many lines as you need and they will all be formatted.
Does it work with non-JSON logs?: The tool is designed for JSON-structured logs. Plain text logs are displayed as-is without additional formatting.
Can I filter logs by severity level?: Yes. You can filter by common log levels like error, warn, info, and debug to focus on the entries that matter most.