Log Viewer · Free Local Tool

Log Level Filter

Identify TRACE, DEBUG, INFO, WARN, ERROR, FATAL, and filter the output according to levels and keywords.

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What are the Log Level Filtering and Coloring Tools?

Identify TRACE, DEBUG, INFO, WARN, ERROR, FATAL, and filter the output according to levels and keywords. ToolHub places the core computing entirely within the browser, allowing immediate use on both desktop and mobile devices, without the need to register an account or send content to the backend.

How to use this tool?

  1. Enter the data according to the field prompts and select the required processing method.
  2. Click "Process Now" to view the results, indicator summary and necessary error messages.
  3. After confirming that the content meets actual needs, you can copy the results or download them into files for further use.

Suitable use cases

Application logs, CI logging, server debugging and incident investigation. All processing is completed in the current page, which is especially suitable for workflows that do not want to post internal data to remote services.

Interpretation of results and precautions

Non-standard formats may not be able to automatically recognize the level, so keyword assistance can be used instead. Tools will validate basic input formats and provide readable error messages, but production environments should still be reconfirmed against source specifications, business rules, or professional requirements.

Browser and device support

Log Level Filter supports current Chrome, Edge, Firefox, and Safari releases. Mobile and desktop layouts use the same validation rules documented on this page.

Frequently Asked Questions

Will the log level filtering and coloring tools upload data to the server?
No. Tool functions are executed directly within the current browser tab, and input and generated results will not be uploaded or saved by ToolHub.
What use cases are the Log Level filtering and coloring tools suitable for?
Application logs, CI logging, server debugging and incident investigation
Do I need to install software before using the Log level filtering and coloring tools?
No need. Use a desktop or mobile browser that supports modern JavaScript, and no account is required.
What are the limitations of this tool?
Non-standard formats may not be able to automatically recognize the level, so keyword assistance can be used instead.
Is manual inspection required after the results are generated?
Needed. Tools can assist with calculations, conversions, or formatting, but before going online, importing data, or making business decisions, the results should still be reviewed according to actual specifications.

Log Level Filter: inputs, output, and reproducible example

Use the free Log Level Filter online. Fast, private, mobile-friendly, and processed directly in your browser.

What this page actually processes

FieldControlDefault exampleValidation role
Show LevelTextWARN,ERROR,FATALShow Level is read by the browser as a text value before the tool runs.
KeywordsTextInput 2Keywords is read by the browser as a text value before the tool runs.
Log ContentMultiline text2026-08-21 INFO server started 2026-08-21 WARN cache is nearly full 2026-08-21 ERROR connection failed 2026-08-21 DEBUG retry payloadLog Content is read by the browser as a multiline text value before the tool runs.

Reproduce the built-in example

Start with Show Level = WARN,ERROR,FATAL; Keywords = Input 2; Log Content = 2026-08-21 INFO server started 2026-08-21 WARN cache is nearly full 2026-08-21 ERROR connection failed 2026-08-21 DEBUG retry payload, then run Log Level Filter. Change one input at a time so the effect on the result remains traceable.

After validating show level, keywords, log content, the page displays its result in the output workspace and enables the relevant copy or download action.

When to use it and how to interpret the result

Application logs, CI logging, server debugging and incident investigation. All processing is completed in the current page, which is especially suitable for workflows that do not want to post internal data to remote services.

Limits and checks before use

Non-standard formats may not be able to automatically recognize the level, so keyword assistance can be used instead. Tools will validate basic input formats and provide readable error messages, but production environments should still be reconfirmed against source specifications, business rules, or professional requirements.

Page verification record

Controls inspected3 documented inputsResult pathValidate → process → review → copy/downloadLast content review2026-09-02