Skip to content
Skip to content
JSON Prism logo
JSON Prism
Open App
Strict mode

JSON Trimmer

Clean permissive input so it becomes strict JSON ready for tooling and production systems.

Open JSON TrimmerAll tools
  • Remove comments and trailing commas
  • Normalize loose input
  • Prepare data for strict parsers

Practical guide

Build, validate, and reuse JSON with less friction.

A focused walkthrough for deciding when the tool fits your workflow.

The JSON Trimmer converts loose, permissive JSON-like input into strict, spec-compliant JSON by removing comments, trailing commas, and other syntax that standard parsers reject. Config files, scaffolding output, and hand-edited payloads frequently include these extras because editors like VS Code accept them. The moment that data hits a production parser, import tool, or API endpoint, the extras cause failures. The trimmer strips them out in one step.

How to use the JSON Trimmer

  1. Paste your loose JSON, JSON5, or JSONC input into the editor.
  2. The trimmer scans for comments (// inline, /* */ block), trailing commas, and other non-standard syntax.
  3. Review the cleaned output in the right panel.
  4. Confirm nothing meaningful was removed — comments that document intent are stripped; data values are untouched.
  5. Copy the clean output and pass it to your validator, converter, or import pipeline.

What it fixes

  • // and /* */ comments that are valid in JSON5 or JSONC but not in standard JSON
  • Trailing commas after the last element in arrays and objects
  • Leading commas and other formatting patterns that some editors tolerate but parsers reject
  • Extra whitespace around structural characters that causes parse failures in strict environments
  • Mixed quote styles left over from template generation

JSON code example

The following is a typical VS Code settings.json fragment — valid JSONC but invalid strict JSON:

JSON
{
  // Editor preferences
  "editor.tabSize": 2,
  "editor.formatOnSave": true,
  "files.exclude": {
    "**/.git": true,
    "**/.DS_Store": true,
    "node_modules": true,  /* large folder, always excluded */
  }
}

After trimming, all comments and the trailing comma inside files.exclude are removed, leaving a payload that any JSON parser will accept.

When to use it

  • JSON5 or JSONC cleanup. You use a permissive format during development because it supports comments, but your build step or API endpoint requires strict JSON. Trim before the handoff.
  • Legacy config migration. An old tool emitted annotated config files. You want to import them into a new system that reads only strict JSON without manually stripping every comment.
  • Vendor payload normalization. A third-party service sends payloads that include trailing commas in arrays. Your parser rejects them. Trim on ingestion before processing.
  • Pre-validation cleanup. You want to run the JSON Formatter or a schema validator but the input has too much noise to parse at all.

Related tools and articles

  • JSON Formatter — format the clean output for readability once the noise is gone
  • JSON Minimal Mode — reduce a trimmed payload further by keeping only the fields you need
  • Pretty vs Minified JSON — understand the difference between readable and compact representations and when each is appropriate
FAQ

Questions about JSON Trimmer

Everything you need to know before you start.

The JSON Trimmer removes unnecessary whitespace (minifies the JSON), can remove specific keys you specify, strip null values, remove empty arrays and objects, and truncate long string values. It is useful for reducing payload size before sending JSON to an API or an LLM.

Paste your JSON into the JSON Trimmer and click minify. All whitespace outside of string values is removed, reducing file size by 15–30% for typical documents. The output is valid JSON identical in data to the input.

Yes. Enter the key names you want to remove, and the trimmer will recursively delete those keys at every depth in the document. This is useful for stripping debug fields, internal metadata, or sensitive fields before sharing or sending JSON.

For typical JSON with readable formatting (2-space indent), minification saves 15–30% of bytes. For JSON with deeply nested structures and many short keys, the saving can be higher. Combined with gzip compression, the total reduction is usually 70–90%.

Ready to use it?

JSON Trimmer, free & private.

No account needed. Your JSON never leaves your browser.

Launch JSON Trimmer