Analyze a Stack Trace and Find the Root Cause

About this tool

stack-trace-analyzer turns a pasted crash log into a readable map of what failed. It understands common stack trace formats from Java/Kotlin/Scala, Python, JavaScript/TypeScript/Node, Go, Ruby, C#/.NET, Rust, and PHP, then reports the detected language, the reported exception, the root cause at the end of the exception chain, and the first frame that looks like your own code.

Use it when a trace is long, nested, or mixed with framework calls. The analyzer normalizes frame order so the throw or panic site appears first by default, marks each frame as user or framework, and can hide framework frames entirely when you only want the code paths you control. If automatic classification is too broad, add comma-separated Your code prefixes such as com.example, /app/src, or my_service.

Worked example

Input:

Exception in thread "main" com.example.SvcException: could not start
    at com.example.App.start(App.java:42)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:301)
Caused by: java.net.ConnectException: Connection refused
    at java.base/sun.nio.ch.Net.pollConnect(Native Method)
    at com.example.Db.connect(Db.java:17)

Default report highlights:

Language: Java / Kotlin / Scala (auto-detected)
Reported: com.example.SvcException: could not start
Root cause: java.net.ConnectException: Connection refused
First user frame: com.example.Db.connect(Db.java:17)

Set Output to table for a Markdown frame table or json when you want a structured exception chain for another script. Enable Hide framework frames to drop standard-library, package-manager, runtime, and framework frames from the displayed output.

Options and limits

• Language defaults to auto. Force a language for short or truncated traces.
• Output chooses readable report, Markdown table, or JSON.
• Your code prefixes is an allow-list. When set, only functions or file paths matching those prefixes count as user code.
• Hide framework frames removes framework rows from the rendered output but still counts them.
• List frames in call order flips the default innermost-first order to outermost-first.
• Max frames per exception accepts 1 through 2000; the default is 100.
• Input is capped at 200,000 bytes. Paste the failing trace rather than an entire application log.
• The parser is heuristic. It does not execute code, fetch source maps, symbolicate minified JavaScript, de-obfuscate Java class names, or reconstruct frames missing from the pasted trace.

FAQ