CSV file viewer

Free Online Log File Viewer for CSV, TSV, and Log Files

Quickly view, search, and filter your log files online with this free tool. Whether you're a developer debugging application logs or just need to explore a CSV file, this viewer makes it easy to find what you're looking for. Drag and drop your file and start searching instantly.

Built with care by the developers at Jam. Open source, ad-free, and works entirely in your browser.

How to Use the Log File Viewer

This tool works with CSV files, TSV files, and plain text log files. It automatically detects the file format and displays your data in an easy-to-read table.

• Upload your file:
  Drag and drop any .csv, .tsv, .txt, or .log file into the upload area, or click to browse.
• Search instantly:
  Use the search bar to find any text across all columns. Matches are highlighted in yellow for easy spotting.
• Filter by values:
  Click on column headers to filter by specific values. Great for narrowing down logs by service, host, or any other field.
• Mark rows for tracing:
  Click the # column to mark important rows. Use Cmd/Ctrl+click to create a second trace flow in a different color.
• Expand for details:
  Click any row to see the full content of each field.

Dev Mode for Log Analysis

Toggle Dev Mode to unlock advanced features designed for developers analyzing application logs. When enabled, you'll see color-coded severity levels (error, warning, info, debug) and a Datadog-style sidebar for filtering by log level and other attributes.

Dev Mode is automatically enabled when the tool detects log-like files. For regular CSV data files, it stays off to give you a clean, simple table view.

Works with Any CSV or Log File

This viewer handles a wide variety of file formats and use cases. It's perfect for exploring data exports, analyzing server logs, reviewing application traces, or just quickly searching through any tabular data.

• Application logs: Debug errors, trace requests, and analyze service behavior.
• Server logs: Review access logs, error logs, and system events.
• Data exports: Explore CSV exports from databases, spreadsheets, or analytics tools.
• Custom log formats: Works with any comma, tab, or semicolon-separated file.

More CSV and Data Utilities

Jam offers a collection of free developer tools for working with data. Convert between formats, parse files, and debug faster.

• CSV to JSON Converter: Convert CSV files to JSON format for APIs and web applications.
• JSON to CSV Converter: Transform JSON data into CSV for spreadsheets and data analysis.
• HAR File Viewer: Analyze HTTP Archive files to debug network requests and performance.
• JSON Formatter: Beautify and validate JSON data for easier reading.

FAQs

• What file types are supported?
  The viewer supports .csv, .tsv, .txt, and .log files. It automatically detects whether your file uses commas, tabs, or semicolons as delimiters.
• Is my data secure?
  Yes. All processing happens entirely in your browser. Your files are never uploaded to any server.
• Can I use this for large files?
  Yes. The viewer is optimized for performance and can handle files with thousands of rows. Facet filtering is limited to the most common values to keep things fast.
• What is Dev Mode?
  Dev Mode enables log-specific features like color-coded severity levels and advanced filtering. It's automatically enabled for log files and can be toggled manually for any file.
• How do I trace multiple flows?
  Click the # column to mark rows for your first trace (blue). Hold Cmd/Ctrl and click to create a second trace (green). Each trace has independent numbering.
• Can I filter by multiple values?
  Yes. Use the sidebar or column header dropdowns to select multiple values. The viewer shows rows matching any of the selected values.
• How do I search for specific text?
  Type in the search bar at the top. The viewer searches across all columns and highlights matches in yellow.
• Does this work offline?
  Once the page is loaded, yes. Since all processing happens in your browser, you can use it without an internet connection.