---
title: "Compare Two JSON Files Locally - Blobster Guide"
description: "Compare two JSON or YAML files in your browser without a diff website. A structural diff by path that ignores key order and matches array items by id."
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language: "en"
generated_from: "prerendered HTML"
---

> Canonical HTML: [https://www.mochavi.com/blobster/guides/compare-json-files-locally](https://www.mochavi.com/blobster/guides/compare-json-files-locally)
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Compare guide

# Compare two JSON files without uploading them.

Open the first file in Blobster, open the Compare pane and choose the second file. Blobster lists every changed, added, removed and retyped value with its path, ignores key order and matches array items by their id where it can. Both files stay in your browser.

Published 14 October 2026 4 minute read By Mochavi

[Install Blobster](https://chromewebstore.google.com/detail/blobster/epddolhfilamhbnmgglenceabjbbeeho) [Read as Markdown](https://www.mochavi.com/blobster/guides/compare-json-files-locally.md)

Short answer

Use Blobster’s Compare pane when you want to know which values changed between two versions of a payload or config you should not upload. Use a text diff when the formatting, comments or key order are the change you care about.

## Key points

-   Each difference is listed as changed, added, removed or type, with a JSONPath-style path and the values before and after.
-   Key order and whitespace are not differences.
-   Arrays of objects are matched by the first field that is present and unique in both files, from `id`, `_id`, `uuid`, `key`, `code` and `name`. Other arrays are compared by position.
-   The second file is read from disk and parsed in the browser, up to the raw-first size limit (25 MB by default).

## Steps

-   Open the first file in Blobster from disk, a paste or a URL.
-   Open Compare in the side pane, or run Compare with file from the command palette.
-   Choose the second file. Blobster parses it by its file name, so a YAML file can be compared with a JSON file.
-   Read the summary, such as `3 differences · 2 changed · 1 added`, then the list below it.
-   Click a changed or removed value to jump to it in the first document.

## What the result looks like

In this example the second file moves `version` to the end, lists the users in a different order with their keys reordered, changes one email address and adds a user. Blobster reports three differences. The reordering does not count, because the users are matched by `id`.

Differences between two versions of a users file

```
changed  $.version             1 → 2
changed  $.users[id=2].email   "bo@example.test" → "bo@example.org"
added    $.users[id=3]         {"id":3,"email":"cy@example.test","role":"viewer"}
```

## Where a structural diff is the wrong tool

Blobster compares parsed values, so it does not report changes to formatting, comments or key order. When those are the change, use a line diff.

Arrays without a shared id field are compared by position. Inserting one item near the start of such an array makes every later item look changed.

The list shows the first 5,000 differences. Blobster does not produce a patch or merge the two files.

For diffs in a script or a CI job, sort the keys first and compare text, for example with `diff <(jq -S . before.json) <(jq -S . after.json)`. jq’s `-S` option outputs object keys in sorted order.

## Why not a diff website

Pasting two versions of a production response, a customer config or an export into a diff site means trusting that site with both. Blobster reads the second file from disk into the extension and keeps both there. It compares your current draft too, so local edits to the first document are included.

## Sources

-   [jq manual (see --sort-keys)](https://jqlang.org/manual/)
-   [Blobster privacy policy](https://www.mochavi.com/privacy/blobster)

Related

[Query JSON with JSONPath→](https://www.mochavi.com/blobster/guides/query-json-with-jsonpath)[Convert YAML to JSON locally→](https://www.mochavi.com/blobster/guides/convert-yaml-to-json-locally)[Open large JSON files→](https://www.mochavi.com/blobster/guides/open-large-json-files)

Machine-readable

[Markdown version→](https://www.mochavi.com/blobster/guides/compare-json-files-locally.md) [Blobster RSS feed→](https://www.mochavi.com/blobster/feed.xml)

Local-first workbench

## Inspect the data. Keep the document local.

Open JSON, logs, tokens, configs and tables in Blobster without adding an account, telemetry or a public paste URL.

[Install from Chrome Web Store](https://chromewebstore.google.com/detail/blobster/epddolhfilamhbnmgglenceabjbbeeho)