JSON Editor Online

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How to edit JSON online

1. Load your JSON. Paste it into the code pane, click Open file, or drop a file on the page. Your last draft is restored automatically when you come back.
2. Edit in either pane. Type in the code pane, or click a key or value in the tree to change it in place. Each change in one pane updates the other.
3. Watch the status bar. It shows Valid JSON with a key count, or the exact line and column of the first error. Click the error to jump to it. The bad line is also marked in red in the line numbers.
4. Tidy and save. Format, Minify or Sort keys, then Download the file or Copy it to the clipboard.

Code mode and tree mode, side by side

Most online JSON editors make you switch between a text view and a tree view. Here both are open at once, because each is better at different jobs:

The tree follows the code pane. While the code has a syntax error, the tree shows the last valid version and is read-only, so a half-typed edit can never overwrite your text. When you edit in the tree, the code is rewritten with your current indentation. Number literals, key order and escapes are kept exactly.

Editing values in the tree

Click a value, type a new one and press Enter (Esc cancels). What you type is read as JSON first. If it is not valid JSON, it is stored as a string, so plain text needs no quotes:

Click a key to rename it. The + button on an object adds a new key and puts it in edit mode. On an array it appends an item. Copy duplicates a node right after itself, and × deletes it. Every tree edit can be undone.

Toolbar reference: format, minify, sort and repair

For a stand-alone formatter with more clean-up options and error excerpts, use the JSON formatter and cleaner. To read a very large file without editing it, the JSON viewer loads branches on demand.

Keyboard shortcuts

Editing JSON files safely

• Large numbers survive. Many editors silently round 64-bit IDs like 9007199254740993 because they go through JavaScript numbers. This editor keeps number text exactly as written, even when you edit other parts in the tree.
• Duplicate keys are flagged. JSON technically allows them, but most parsers keep only the last value. The status bar warns you when a document has any.
• Encoding. Downloads are saved as UTF-8 without a byte-order mark, which is what RFC 8259 requires for JSON exchanged between systems.
• Your draft stays local. The current text is autosaved to this browser's local storage so a reload does not lose work. Clear removes it. It is never sent anywhere.
• Structure is not the same as correctness. Valid JSON can still be missing a required field. To check shape and types, test it against a JSON Schema in the JSON validator.

Edit JSON in code

Node.js

import { readFileSync, writeFileSync } from 'node:fs';
const cfg = JSON.parse(readFileSync('config.json', 'utf8'));
cfg.server.port = 8080;
delete cfg.legacy;
writeFileSync('config.json', JSON.stringify(cfg, null, 2) + '\n');

Python

import json
with open("config.json", encoding="utf-8") as f:
    cfg = json.load(f)
cfg["server"]["port"] = 8080
cfg.pop("legacy", None)
with open("config.json", "w", encoding="utf-8") as f:
    json.dump(cfg, f, indent=2, ensure_ascii=False)

jq

jq '.server.port = 8080 | del(.legacy)' config.json > tmp.json && mv tmp.json config.json
jq '.users += [{"name": "Ada"}]' users.json      # append to an array

Frequently asked questions