onDevTools JSON Formatter
What onDevTools JSON Formatter is
onDevTools JSON Formatter is a free browser tool for formatting, validating, querying, comparing, and transforming JSON. It can pretty-print or minify data, indent it with 2, 4, or 8 spaces, and optionally sort keys alphabetically. Parsing supports strict RFC 8259 / ECMA-404 JSON and JSONC comments and trailing commas, but not JSON5. Schema validation uses JSON Schema Draft 2020-12 and reports violations with JSON Pointer paths. Its JSONPath query engine supports wildcards, recursive descent, slices, and filters. The tool can compare documents side by side and produce a JSON Merge Patch; transforms include flattening or unflattening JSON and removing null or empty values. A collapsible tree view offers full-text search and copying of node values or JSON Pointer paths. The maker says parsing, validation, schema checks, diffs, and transforms run locally in the browser, without uploading JSON. The tree view and JSONPath can slow noticeably above about 1 MB or 50,000 nodes, and numbers above 2^53 − 1 may lose precision. The free plan costs nothing and requires no account.
Who it suits
This tool suits developers working with API responses, configuration files, or production payloads in a browser. It offers JSON validation, querying, comparison, and transformation without uploading JSON, according to the maker.
What it does well
- Free plan requires no account.
- Supports JSON Schema Draft 2020-12 validation.
- JSONPath queries include filters and recursive descent.
- The maker says JSON processing runs locally.
What to know first
- JSON5 is not supported.
- Tree view and JSONPath can slow above about 1 MB or 50,000 nodes.
- Numbers above 2^53 − 1 may lose precision.
- Streaming and JSON Lines are out of scope.
Limits
The free plan is listed as free. Above about 1 MB or 50,000 nodes, the tree view and JSONPath can slow noticeably; streaming and JSON Lines are out of scope, and numbers above 2^53 − 1 can lose precision.
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Free | Free online JSON formatting and validation; no account required | Free |
As ondevtools.com lists them, read 7 Oct 2026. The maker's own page has the final word.
Verdict
onDevTools JSON Formatter brings common JSON editing, validation, querying, comparison, and transformation tasks into a browser tool. Large inputs and high-precision numbers have stated limitations.
Questions
How much does onDevTools JSON Formatter cost?
The Free plan costs nothing.
Is there a free plan or trial?
A free plan is available, and no account is required for free online formatting and validation. There is no free trial.
Which platforms does it support?
The listed platform is web.
Does it support JSONPath and JSON diffing?
Yes. Its JSONPath engine supports wildcards, recursive descent, slices, and filters. It compares documents side by side and can produce a JSON Merge Patch.
Does it upload JSON?
The maker says parsing, validation, schema checks, diffs, and transformations run locally in the browser, and JSON is not uploaded.
Who makes onDevTools?
The About page identifies Onur Kat as an SAP Certified SAP Commerce Developer and DevOps Engineer.
Facts from onDevTools JSON Formatter's own pages
- Diff
- Compares JSON documents side by side and can produce a JSON Merge Patch. · ondevtools.com, 7 Oct 2026
- Formatting
- Pretty-prints or minifies JSON with 2-, 4-, or 8-space indentation and optional alphabetical key sorting. · ondevtools.com, 7 Oct 2026
- Intended audience
- The maker presents onDevTools as a toolkit for developers and says the JSON tool can handle API responses, configuration files, and production payloads in the browser. · ondevtools.com, 7 Oct 2026
- JSON modes
- Supports strict RFC 8259 / ECMA-404 parsing and JSONC comments and trailing commas; JSON5 is not supported. · ondevtools.com, 7 Oct 2026
- JSONPath
- Provides an RFC 9535 JSONPath query engine with wildcards, recursive descent, slices, and filters. · ondevtools.com, 7 Oct 2026
- Large input limit
- The maker says the tree view and JSONPath become noticeably slower above about 1 MB or 50,000 nodes; streaming and JSON Lines are out of scope. · ondevtools.com, 7 Oct 2026
- Maker
- The About page identifies Onur Kat as an SAP Certified SAP Commerce Developer and DevOps Engineer. · ondevtools.com, 7 Oct 2026
- Number precision
- Numbers larger than 2^53 − 1 can lose precision because the parser uses IEEE-754 doubles; the maker recommends representing 64-bit IDs as strings. · ondevtools.com, 7 Oct 2026
- Privacy
- The maker says parsing, validation, schema checks, diffing, and transforms run locally in the browser and JSON is not uploaded. · ondevtools.com, 7 Oct 2026
- Purpose
- Formats, validates, queries, diffs, and transforms JSON in the browser. · ondevtools.com, 7 Oct 2026
- Schema validation
- Validates against JSON Schema Draft 2020-12 and reports violations with JSON Pointer paths. · ondevtools.com, 7 Oct 2026
- Transforms
- Can flatten and unflatten JSON, remove nulls or empty values, and minify output. · ondevtools.com, 7 Oct 2026
- Tree navigation
- The collapsible tree view supports full-text search and copying a node's value or JSON Pointer path. · ondevtools.com, 7 Oct 2026
Where onDevTools JSON Formatter stands on Freedom251
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