JSON Guide: Format, Validate and Convert
Scenario 1: JSON errors — format first, then hunt
The most common pain when writing configs or testing APIs is a stray comma. Open HeronTool's JSON Formatter:
- Paste your JSON;
- Click format — indentation and line breaks are applied automatically;
- If the syntax is invalid, the tool points out the error position (line/column); fix it there and then.
Once formatted, the structure is obvious: key-value hierarchy, missing brackets and commas reveal themselves instantly.
Scenario 2: Minify and validate
- JSON Minify: strip whitespace for storage and release — smaller payloads;
- JSON Validator: check whether a JSON document is legal and on which line the error is;
- JSON Viewer: turn deeply nested JSON into a collapsible tree — API responses become readable at a glance.
Scenario 3: Convert between formats
- JSON ↔ CSV: table data to API data and back, via JSON to CSV and CSV to JSON;
- JSON ↔ YAML: migrating config files (JSON to YAML / YAML to JSON);
- JSON ↔ XML: connecting legacy systems (JSON to XML / XML to JSON);
- JSON ↔ TOML: modern config conversion (JSON to TOML / TOML to JSON);
- JSON → TypeScript: auto-generate TS type definitions from API data (JSON to TypeScript).
FAQ
Q: Must JSON keys use double quotes?
Yes. The spec requires double quotes for keys and strings; single quotes or bare keys are not valid JSON (only JS object literals allow them).
Q: How do I handle dates in JSON?
JSON has no date type; the convention is ISO 8601 strings (e.g., "2026-08-28T10:00:00Z") or Unix timestamps.
Q: Why can't JSON have comments?
By design — to keep the format clean and parsing consistent across languages. Use JSONC or YAML when comments are needed.
In summary
Format to see structure, minify to save bytes, validate to catch errors, convert to bridge formats — HeronTool turns everyday JSON chores into free online tools. Paste, use, done, all processed locally with no uploads.