An indented tree showing student, courses and progress, plus a JSON-compatible representation of the accepted literal.
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Python List & Dictionary Visualizer
Turn a Python list, tuple, set or dictionary literal into a collapsible-style indented tree and valid JSON-compatible output.
Free to useNo sign-upRuns in your browser
PyList & Dictionary VisualizerReal Python in an isolated browser worker
Python runtime preparing…
Your result will appear here.
A WORKED TASK
See how a nested Python literal is arranged
The student example has a dictionary at its root, a list under courses and another dictionary under progress. Visualize it to distinguish keys, nested containers and individual values. Try adding a new course inside the list rather than adding an unrelated top-level key.
This reads literals, not arbitrary Python expressions or executable objects. Sets and tuples may become JSON-compatible sequences; their original type and set order are not guaranteed in JSON output.
What to check
- Paste a literal, not a variable assignment such as data = {...}.
- Use the Python literal names True, False and None when appropriate.
- Keep each string quoted and balance all brackets before checking a large structure.
TESTED & REVIEWED
Know what this tool does—and where to double-check
- Reviewed by
- HTML Online Viewer project
- Last reviewed
- Processing
- Code and supported files are processed in this browser tab. Runtime tools download Python WebAssembly, but do not intentionally upload your source.
- Important limitation
- The browser runtime is intentionally isolated and may not include every desktop package, system command or network feature. Verify production programs in their target Python environment.
EXAMPLE INPUT
Start small, then use your own data
Python literal
{"student": "Amina", "courses": ["HTML", "CSS", "JavaScript"], "progress": {"completed": 18, "total": 22}}An indented tree showing student, courses and progress, plus a JSON-compatible representation of the accepted literal.
COMMON QUESTIONS
List & Dictionary Visualizer FAQ
Does this upload my code or files?
No. Processing happens locally in your browser. Runtime tools download Python itself, but your source is not sent to our server.
Why can the first Python run take longer?
The browser downloads and starts the Python WebAssembly runtime. Later runs in the same tab are normally much faster.
Can I stop a program that takes too long?
Yes. Runtime tools show a Stop button while Python is working. Stopping terminates the isolated worker and a clean runtime starts when needed.