Drag & Drop Upload
Drop any .log, .txt, .out, or .err file directly onto the viewer. Instant rendering — no page reload.
Upload any .log file and instantly view, search, filter, and analyze log entries with intelligent error detection, syntax highlighting, and one-click export.
Supports .log, .txt, .out, .err, .trace — up to 50 MB
Files are processed entirely in your browser. Nothing is uploaded to any server.
From instant error detection to smart search — built for developers, sysadmins, and QA engineers.
Drop any .log, .txt, .out, or .err file directly onto the viewer. Instant rendering — no page reload.
Automatically identifies ERROR, WARN, INFO, and DEBUG lines with color-coded highlighting and severity counts.
Instant keyword search with match highlighting. Wrap your query in /slashes/ to activate full regex mode.
One-click filters for ERROR, WARN, INFO, and DEBUG levels. Combine with search for surgical log analysis.
Timestamps, IP addresses, file paths, HTTP status codes, and stack traces all receive distinct color treatment.
Every line is numbered for easy reference during debugging sessions or when collaborating with teammates.
Download the currently visible (filtered) lines as a .txt file, or copy them to clipboard with one click.
Your log data never leaves your machine. Everything runs in JavaScript — no server uploads, complete privacy.
Handles log files up to 50 MB with a virtual scroll engine that keeps the browser responsive on massive files.
Three steps from upload to analysis — no account, no software, no waiting.
Drag your .log file onto the drop zone, click to browse your device, or paste raw log text directly into the text area below the tool.
The viewer renders your file instantly with line numbers, severity coloring, and timestamp highlighting. Scroll through any size file smoothly.
Use the search bar to find keywords or regex patterns. Click ERROR, WARN, INFO, or DEBUG buttons to isolate lines by severity level.
Download filtered log lines as a .txt file or copy them to clipboard. Share only the relevant entries with your team.
A LOG file is a plain-text record generated automatically by operating systems, web servers, applications, and network devices. Every meaningful event — from a user login attempt to a server-side exception — is appended as a timestamped entry. Developers, system administrators, and DevOps engineers rely on log files daily to diagnose crashes, trace performance bottlenecks, audit security events, and verify that automated pipelines executed correctly.
The challenge is that log files are often enormous — sometimes hundreds of megabytes — packed with thousands of lines spanning days or weeks of activity. Without a dedicated log file viewer, hunting through raw text in a basic editor is painstaking and error-prone. A proper log analyzer highlights critical severity levels, lets you search with regex, and presents statistics at a glance so you can reach actionable insights in seconds rather than hours.
Our free online LOG file viewer lets you open and read LOG files directly in your browser without installing Notepad++, TextPad, Visual Studio, or any desktop application. Paste a URL, drop a file, or type raw log text — the tool parses the content instantly on your device. Because all processing happens client-side in JavaScript, your sensitive log data never touches a remote server, making this approach secure for production and internal logs alike.
The viewer supports virtually every common log format: Apache and Nginx access logs, Linux syslog and auth.log files, Windows Event Log exports, Java stack traces, Python tracebacks, JSON-structured logs from Node.js and Go applications, and generic timestamped application logs from frameworks like Log4j, Logback, Winston, and Monolog. If the file ends in .log, .txt, .out, or .err, this tool can read it.
Beyond raw display, this log reader provides real-time keyword search with regex support — simply wrap a pattern in forward slashes (e.g., /\b5\d{2}\b/) to activate regex mode. One-click level filters for ERROR, WARN, INFO, and DEBUG allow you to cut through noise instantly. Intelligent syntax highlighting distinguishes timestamps, IP addresses, HTTP status codes, file paths, and exception class names with distinct colors, making patterns recognizable at a glance. Line numbers give you a precise reference point when communicating issues with colleagues. The export feature lets you download exactly the filtered subset you need as a clean .txt file.
Log viewers serve every team touching software infrastructure. Developers use them to trace 500-series errors back to specific code paths. QA engineers compare expected versus actual log output during regression testing. Security analysts scan auth.log and access.log entries for brute-force patterns or unauthorized access. DevOps teams monitor deployment logs for rollback triggers. Support engineers open customer-submitted logs to reproduce reported bugs. A fast, browser-based log file reader removes the friction of tool setup so any team member can open and understand a log file in under thirty seconds — regardless of their operating system or technical environment.
Everything you need to know about opening and analyzing LOG files online.
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