There is the "Compare" plugin. You can install it via Plugins -> Plugins Admin... (or Plugins -> Plugins Manager in older versions of Notepad++) in the top menu.
Alternatively you can install a specialized file compare software like WinMerge.
Answer from Lars Fischer on Stack OverflowHey all,
So I’m taking over a role for a coworker managing content for our site in AEM. We have three AEM environments: we make changes in the lower one and push it to the middle environment to test it before pushing the middle to production.
Part of the testing involves comparing JSONs between the lower and middle environments to ensure they match. Right now, we do this in Notepad++ by copying the JSON code from each environment and doing a simple compare. This is incredibly time consuming so I am looking to automate the process. Something as simple as, here’s a list of lower/middle environment JSONs side by side; compare these and return if they match or not.
I typically work in Excel and code in VBA since it’s a program everyone in the enterprise has so there’s no special access required. In researching I’ve noticed Python makes JSON compare pretty easy but I haven’t really seen any automated JSON compare code. Could anyone point me in the right direction?
Thanks all!
Videos
There is the "Compare" plugin. You can install it via Plugins -> Plugins Admin... (or Plugins -> Plugins Manager in older versions of Notepad++) in the top menu.
Alternatively you can install a specialized file compare software like WinMerge.
Update:
- for Notepad++ 7.5 and above use Compare v2.0.0
- for Notepad++ 7.7 and above use Compare v2.0.0 for Notepad++ 7.7, if you need to install manually follow the description below, otherwise use "Plugin Admin".
I use Compare plugin 2 for notepad++ 7.5 and newer versions. Notepad++ 7.5 and newer versions do not have plugin manager. You have to download and install plugins manually. And YES it matters if you use 64bit or 32bit (86x).
So Keep in mind, if you use a 64-bit version of Notepad++, you should also use a 64-bit version of the plugin, and the same is valid for 32-bit.
I wrote a guideline how to install it:
- Start your Notepad++ in administrator mode.
- Press F1 to find out if your Notepad++ is 64bit or 32bit (86x), hence you need to download the correct plugin version. Download Compare-plugin 2.
- Unzip Compare-plugin in a temporary folder.
- Import the plugin from the temporary folder.
- The plugin should appear under the Plugins menu.
Note:
It is also possible to drag and drop the plugin.dllfile directly in the plugin folder.
64bit:%programfiles%\Notepad++\plugins
32bit:%programfiles(x86)%\Notepad++\plugins
Update Thanks to @TylerH for this update: Notepad++ Now has "Plugin Admin" as a replacement for the old Plugin Manager. But this method (answer) is still valid for adding plugins manually for almost any Notepad++ plugins.
Disclaimer: the link to this guideline refer to my personal website.
You might be able to use a JSON formatter to accomplish the task (since it would likely complain or do something wrong -- say, like indent improperly -- if the JSON's invalid). See Is there an extension to reindent JSON in Notepad++?. Similarly, there's a JSONViewer Notepad++ plugin the might help in the same way.
Another less-than-ideal alternative would be to just use one of the online JSON validators.
There is plugin for NPP+ called JSLint. It is a plugin to validate JavaScript-code, but it works also just fine with JSON-files.
Is there a tool that can extract the json values to be altered in a manner less manual and more clean than using a straight text editor?
One of my recent tasks involves syncing aggregated metrics from our data warehouse to a marketing platform so that the marketing team can make campaigns that target, for example, all users that made 5 or more orders in the last week.
Due to limitations with the marketing platform’s reporting api, we have to download all of the existing data at once instead of by user. This requires downloading a 1 gigabyte text file, filtering out the random attributes we didn’t write, and comparing each user with the existing data in our data warehouse.
The goal is to end up with a list of JSON objects to send to the marketing platform api that only contain the changed attributes because the platform charges us by the attribute.
What’s the best way to compare two giant lists of json objects by user id and only return the attributes that are different?
Right now I’m loading both into pandas dataframes and running a comparison, but it eats up a ton of memory and takes a while.
You can use Codverter JSON Validator, it`s online and highly secure, everything you do is interpreted on your local computer and never sent back to the server.
the validation error messages are informative and accurate.
(Full Disclosure: I am one of the developers).

The "Format JSON" option of the JSON Viewer will give an error if the JSON is not correct and also will select the incorrect text.
If the JSON is correct it will reformat but you can use undo (Ctrl+Z) to get it back to the previous format.