What is a good MongoDB GUI client?

Robo 3T (formerly known as RoboMongo)

Shell-centric cross-platform open source MongoDB management tool (i.e. Admin GUI).

[It] embeds the same JavaScript engine (based on Mozilla SpiderMonkey), that powers MongoDB's mongo shell. It means that you can reuse your existing skills of MongoDB Shell in Robomongo.

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Some more info:

• It's available for Linux, OSX and Windows.
• Regarding Linux, there are packages available in the .rpm (Fedora, CentOS, openSUSE), .deb (Debian, Ubuntu) and .tar.gz formats.
• It is free (as in Speech); you can access its GitHub repository here.

One thing I know of (but don't like the interface very much) is UMongo, which is a desktop, not browser-based application. Here's a screenshot:

So far I've been using MonjaDB - it's an Eclipse plug-in, and Eclipse is my IDE anyway. I like it; it seems to have all the features I used to use in RockMongo.

Here's a screenshot from MonjaDB (there are more on his website, as well as some instructions):

To install it, you obviously need Eclipse (which you can get from the Ubuntu repositories). Once you've done that you need to go to the Help-> Install New Software... and then add this update site. Although I like it, I don't think many people will switch IDE's just for a GUI for Mongo (although I could be mistaken).

Both UMongo and MonjaDB have their source code is on GitHub.

You can check out mongobooster. MongoBooster is a shell-centric cross-platform GUI tool for MongoDB v2.2-3.2, which provides update-in-place, Lodash & Moment.js integration, ES6 syntax support and true intellisense experience.

MongoBooster has the following features:

1. MongoBooster offers true IntelliSense experience. The build-in language service knows all possible completions, methods, properties, variables, key words, even the MongoDB collection names, field names and operators. The IntelliSense suggestions will pop up as you type.
2. In the script editor, parameter hints will pop up as you're typing a method invocation.Handy date range snippets, SQL to MongoDB conversion snippets...
3. The mouse hover will show many useful information, such as types of symbols, function definition, type information and document.
4. Matching brackets will be highlighted as soon as the cursor is near one of them.
5. Everything MongoBooster can do is in the Command Palette. See it by using shortcuts CTRL-SHIFT-P
6. SSH tunneling for MongoDB connections
7. Simple management of shards and replica sets
8. There is a free license with some limitations.

Disclaimer: I work for MongoBooster.