How to Open a JSON File: A Practical, Developer-Tested Guide
If you work in software development, you will deal with JSON files sooner or later. APIs return JSON. Config files use JSON. Frontend apps breathe JSON. Yet, opening a JSON file can fail in ways that feel oddly personal.
I have stared at “Unexpected token” errors more times than I want to admit. In most cases, the file looked fine until it wasn’t. This guide explains how to open a JSON file correctly, using real tools, real code, and real fixes I’ve used as a developer.
What Is a JSON File?
JSON stands for JavaScript Object Notation. It is a lightweight data-interchange format designed to be easy for humans to read and machines to parse.
JSON follows a strict specification defined in RFC 8259. It supports objects, arrays, strings, numbers, booleans, and null values. That’s it no comments, no trailing commas, no shortcuts.
Most JSON files use the .json extension and store structured data such as API responses, app settings, and localization strings.
How to Open a JSON File Using a Text Editor
The fastest way to open a JSON file is with a text editor. This method works well when you want to inspect or manually edit the file.
Recommended Editors
- Visual Studio Code
- Sublime Text
- Notepad++
- Atom
I personally rely on Visual Studio Code. Its syntax highlighting saved me countless times when I missed a comma or quote. The editor does not judge but it does underline mistakes immediately.
Right-click the file, select Open With, and choose your editor. If the content appears as unreadable text, the JSON is likely invalid.
How to Open a JSON File in a Web Browser
Modern browsers can open JSON files directly. Chrome, Firefox, and Edge all support JSON rendering.
Drag the file into the browser window or use Ctrl + O.
Firefox formats JSON automatically, which feels like a small gift on busy days.
If everything appears on a single line, the file is still valid. It just lacks formatting.
How to Open a JSON File in Python
Python includes a built-in json module.
It is safe, fast, and reliable for reading JSON files.
This is the approach I use when handling API responses and configuration files.
import json
with open("data.json", "r", encoding="utf-8") as file:
data = json.load(file)
print(data)
The json.load() function converts JSON into Python dictionaries and lists.
This behavior is documented in the official
Python JSON documentation.
Always specify the encoding. I once skipped it and spent an hour debugging emoji-related crashes. That lesson stuck.
How to Open a JSON File in JavaScript
JavaScript offers multiple ways to open JSON files.
For browser-based apps, fetch() works best.
fetch("data.json")
.then(response => response.json())
.then(data => {
console.log(data);
})
.catch(error => {
console.error("Error loading JSON:", error);
});
This method parses JSON automatically when the response is valid. If parsing fails, the error usually points to invalid syntax.
For Node.js, I often use fs.readFile().
It works well for scripts and backend services.
How to Open a JSON File on Windows and macOS
Windows and macOS treat JSON files as plain text. You can open them using Notepad, TextEdit, or any editor.
On macOS, ensure TextEdit is set to plain text mode. Rich text formatting can break JSON instantly. I learned that after watching a file self-destruct on save.
Common Errors Developers Face While Opening JSON Files
I have encountered every error listed below. Most developers do usually under time pressure.
1. Invalid JSON Syntax
Missing commas, quotes, or braces cause this error. JSON syntax is strict and unforgiving.
{
"name": "John"
"age": 30
}
This fails because the comma is missing. Formatting and validating the file revealed the issue immediately.
2. Unexpected Token Error
This error usually appears when comments exist in the file. JSON does not support comments.
Removing comments fixed the issue every time. No exceptions so far.
3. Encoding Issues
Special characters can break parsing if encoding mismatches. UTF-8 is the safest choice.
I now treat encoding as mandatory, not optional.
4. Incorrect File Path
Wrong file paths cause silent failures. Relative paths break often in production environments.
Printing the current working directory helped me locate the issue quickly.
How I Debug JSON Issues as a Developer
I follow a simple checklist before blaming the language or framework.
- Validate JSON structure
- Confirm encoding
- Check file paths
- Load data step by step
I never trust manually edited JSON. Validation tools catch mistakes faster than any debugger.
Best Practices for Working With JSON Files
Use consistent indentation and formatting. Readable JSON prevents mistakes.
Avoid trailing commas and comments. They work in JavaScript but not in JSON.
Validate JSON files before deploying them. This habit saved me from shipping broken releases more than once.
Helpful Tools for JSON Formatting and Validation
Formatting tools improve readability and reduce errors. I use them daily.
For a fast and reliable solution, use our JSON Formatter Pro .
It validates structure, formats content, and highlights syntax issues instantly.
Author Experience
I have worked with JSON files extensively in real-world web and backend projects, including API integrations, configuration management, and production debugging. The examples and errors shared here come from hands-on development experience, not theory or assumptions.
Final Thoughts
Opening a JSON file seems simple. In practice, small mistakes cause big problems.
Understanding the format, using reliable tools, and validating files consistently makes the process smooth and predictable.
JSON follows strict rules. Respect them, and everything works. Ignore them, and your afternoon disappears.