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Open a .json file with any text editor or browser for a quick look; use a code editor to edit and format it, or a terminal tool such as jq or Python to inspect and process it. JSON is plain text, so there is no single required application.
What is a JSON file?
JSON (JavaScript Object Notation) is a lightweight, language-independent format for exchanging data. It stores information as name/value pairs and ordered lists. Because a JSON file is text, you can read it with general-purpose tools rather than a proprietary JSON app. JSON.org describes the format and its structure.
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Open JSON in a browser or text editor
For a small file you only need to inspect, use your operating system’s file-open action and choose a plain-text editor, or open the file in a browser. What the browser shows depends on the browser and how the file is served: it may display raw text, present a formatted view, or download the file. If the file is on your computer, opening it in a text editor is often the most predictable way to see its contents.
Use a code editor to work with JSON
If you need to edit a nested or minified file, a code editor is usually more helpful than a basic text editor. Syntax coloring makes keys, strings, and values easier to distinguish; folding helps collapse nested sections; formatting improves readability; and error cues can help locate malformed JSON. Keep an untouched copy before making changes to important files.
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Inspect or format JSON from a terminal
On systems with these tools available, use less to page through a large file, jq to format it or select a field, or Python’s built-in JSON tool for formatted output and a syntax check.
less file.json
jq . file.json
jq '.field' file.json
python3 -m json.tool data.jsonjq . file.json pretty-prints the document to the terminal; it does not overwrite the source file. The field expression jq '.field' file.json prints the value at the top-level key named field. Replace that name with the key you need. python3 -m json.tool data.json likewise prints formatted JSON and reports a parse error if the input is invalid. The Python command works when Python 3 is installed; jq must be installed separately if your system does not already have it.
Read a JSON file in Python
Use json.load() to parse a JSON document from an open file. Specify UTF-8 when opening the file:
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with open("data.json", "r", encoding="utf-8") as f:
data = json.load(f)After parsing, data contains Python data structures corresponding to the JSON values, such as dictionaries and lists. Python’s documentation describes the JSON module and advises caution when parsing untrusted data. A JSONDecodeError includes the error message and document position, including line and column information, which can help pinpoint a syntax problem.
Format a minified JSON file safely
A JSON document on one long line may still be valid; minification removes whitespace rather than changing the data structure. To make it easier to inspect, format a copy with a code editor, jq, or python3 -m json.tool. Check the formatted result before replacing or saving over the original.
Fix common JSON opening and parsing errors
If a viewer or parser refuses the file, the problem may be invalid syntax rather than the application you used to open it. Standard JSON parsers do not accept comments or other non-standard extensions. Read the reported line and column, then inspect the surrounding syntax.
- Check that strings and property names use double quotation marks.
- Look for a missing or extra comma between items.
- Match every opening brace or bracket with its closing partner.
- Remove comments or syntax extensions if the file must be accepted by a strict JSON parser.
Python’s JSONDecodeError location details and the output from python3 -m json.tool can help narrow down where parsing failed.
Choose a method based on the task
| Method | Best for | Trade-off |
|---|---|---|
| Browser or plain-text editor | A quick look at a small file | Limited help for editing, formatting, or diagnosing syntax |
| Code editor | Regular editing, nested data, and minified files | Requires an editor with JSON features |
jq or Python in a terminal |
Repeatable inspection, formatting, validation, and automation | Requires the relevant tool and comfort with commands |
| Online validator | Checking a non-sensitive sample without setting up a local tool | Uploading data can expose it to the service; do not use for confidential content |
Protect private data and handle untrusted files carefully
Do not paste passwords, API keys, personal records, or other confidential information into an online validator. For private data, use a local editor, jq, or Python instead. Parsing untrusted JSON can also consume substantial CPU or memory, so use sensible size limits when processing inputs from unknown sources, especially in automated systems.
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