Dev
Dummy Stack Trace Generator
Testing an error tracking UI or a log ingestion pipeline requires stack traces that look authentic, but waiting for a real crash to happen in your application is not a repeatable workflow. This generator produces language-idiomatic fake stack traces for JavaScript, Python, Java, Go, and Ruby at a configurable depth, so you can feed your error display component, Datadog parser, or Sentry-style dashboard with realistic input on demand. The language dropdown sets the trace format precisely: JavaScript traces start with an error type like "TypeError: Cannot read properties of undefined" followed by at frames with file paths, function names, and line and column numbers. Python traces begin with "Traceback (most recent call last):" and include paired file/line and code snippet lines. Java starts with "Exception in thread 'main'" and package-qualified class.method(ClassName.java:line) frames. Go uses goroutine headers and package.function() with hex offsets. Ruby follows the from file:line:in 'method' style. The depth input sets the number of frames from 3 to 15. For snapshot tests, generate a trace once and commit it as a static fixture — since file paths and function names are realistic but consistent within a language, the output makes a credible test baseline without changing between runs.
How to use
- Choose your options above
- Click Generate
- Copy your result
Detailed instructions
- Choose the language.
- Set the stack depth.
- Click Generate to produce a result.
- Copy the Generated Stack Trace and use it where you need it.
Use Cases
- •Populating a Sentry-style error dashboard with realistic JavaScript TypeError traces during UI development
- •Seeding a log ingestion pipeline in Datadog or Elasticsearch with mock Python tracebacks for parser testing
- •Stress-testing stack trace truncation logic by generating Java traces at depth 12 or higher
- •Creating debugger tutorial content that shows readers a realistic Go goroutine panic with file paths and line numbers
- •Demoing an error monitoring product to clients using believable Ruby exception traces without touching production
Tips
- →Generate it a few times and keep the version that fits best.
- →Adjust the options above to steer the result toward what you need.
- →Replace the placeholder values with your real data before using it.
- →Everything runs free in your browser — no signup or install required.
FAQ
how to generate fake stack traces for testing error UIs
Select the language your UI is built to parse, set the stack depth to match a realistic exception (6–10 frames is typical), and copy the output directly into your test fixture or mock API response. Each trace includes language-accurate formatting like Python's 'Traceback (most recent call last)' or Go's 'goroutine' prefix, so your parser sees plausible input.
can I use a fake stack trace with Sentry or Datadog
The generated traces are plain-text mock data, not structured SDK payloads, so they won't submit cleanly to live monitoring APIs. They're best used to populate the display layer of your error UI — for example, rendering a pre-loaded trace in a Storybook component or a Cypress fixture — rather than as ingest-ready events.
do fake stack traces look realistic enough for demos or documentation
Yes. Each trace uses language-idiomatic formatting, plausible file paths like src/components/UserList.tsx or /app/models/user.py, and realistic function names, so they hold up in screenshots, screencasts, and client demos. If you need a specific file or function name to appear, paste the output and do a quick find-and-replace before publishing.
what is the minimum and maximum stack depth I can generate
The depth input accepts values from 3 to 15 frames. Three frames is the minimum and represents a shallow, near-surface exception. Fifteen frames simulates a deeply nested call chain, useful for stress-testing truncation logic in error dashboards that limit how many frames they display.
You might also like
Popular tools from other categories that share themes with this one.
Try these next
More free tools from other corners of the catalog, picked by shared themes.