7 Best Free Online JSON Tools in 2026 (Private, No Signup Needed)
The main JSON tools grouped by the job you need to do. All of them run in your browser, so your data is never uploaded.
JSON is easy to paste into a website, and that is the risk: many online JSON tools send your data to a server. The tools below run in your browser instead. Your JSON stays on your device, and none of them needs an account.
We picked the 7 JSON tools on this site that run entirely in the browser. Each entry says what the tool does, when you need it, and how it helps in practice. All 7 are 100% private.
Compare, validate and patch
1. JSON Compare and JSON Diff
Compares two JSON documents by keys, values and data types, ignoring key order. It can also validate against a JSON Schema.
When you need it
- Two API responses differ and you need to find the change.
- A config file was edited and you want to confirm exactly what changed.
Practical use case
An API returns different results in staging and production. Pasting both responses shows the fields whose values or types differ, even when the keys are in a different order.
2. JSON Patch (RFC 6902)
Creates an RFC 6902 JSON Patch from two documents, or applies a patch to a document.
When you need it
- You need to describe a change to a document in a standard form.
- A patch from another system must be checked against a document before it is applied.
Practical use case
A deployment tool expects changes to a config file as an RFC 6902 patch. Creating the patch from the old and new versions gives the exact operations to send, and applying it to a copy confirms the result.
Query and reshape
3. JSON Query (SQL)
Runs a SQL SELECT against pasted JSON, with WHERE, GROUP BY, JOIN and aggregates, entirely in your browser.
When you need it
- You want to count or group records in an exported JSON file without writing code.
- You need to join two JSON lists on a shared ID.
Practical use case
An analyst has an export of 5,000 orders as JSON and needs total sales per country. A GROUP BY query gives the totals directly, and the data stays in the browser.
4. JSON Schema from Sample
Generates a JSON Schema from a sample document, inferring types, required keys and array items.
When you need it
- You have an example payload and need a schema to validate future data.
- You are documenting an API from real responses.
Practical use case
A developer receives a sample webhook payload from a partner with no documentation. A generated schema gives a starting point for validating incoming events. The developer then adds the optional fields that the sample did not show.
5. Minify JSON and Shrink Size
Minifies JSON and removes null values, empty objects, empty arrays and empty strings at any depth.
When you need it
- A JSON payload is larger than it needs to be.
- You want a compact file for a fixture or a mobile app.
Practical use case
A mobile app downloads a catalogue full of null fields. Removing the empty values and minifying the file shrinks it, so the app gets the same information with less data. Check that your code does not depend on null values being present.
6. JSON Escape and Unescape
Escapes plain text as a JSON string, or unescapes a JSON string back to plain text.
When you need it
- You need to put text with quotes or line breaks inside a JSON field.
- A JSON string copied from a log is hard to read.
Practical use case
A support engineer copies an error message from a log, where quotes and line breaks appear as escape sequences. Unescaping it gives the readable text. Escaping works the other way, for a multi-line message that must sit inside a JSON request.
Keep sensitive data out of AI chats
7. Redact JSON for ChatGPT and LLMs
Detects and masks emails, names, IDs and tokens in JSON before you paste it into an AI chat.
When you need it
- You want an AI assistant to help debug a response that contains customer data.
- You are asking for a review of a config that holds keys or tokens.
Practical use case
A developer wants an AI assistant to explain why an API response fails. The response contains an email address and an access token. Redacting them first lets the assistant see the structure without the real values. Check the result before sending, because automatic detection can miss a value.
Which one should you use?
Start with the job, not the tool. To debug a difference between two responses, use JSON Compare. To find a value in a large file, use JSON Query. To share a file with an AI assistant, redact it first with the last tool in the list.
To check the privacy claim yourself, open your browser's developer tools (F12), choose the Network tab, use any of these tools, and see that no request carries your data.
All log analysis tools · All guides
Questions
Are these tools really free?
Yes. Each tool is free to use, with no sign-up needed.
Is my JSON uploaded when I use these tools?
No. Every tool in this list runs in your browser, so your JSON stays on your device and is never uploaded.