#1: πfs
It’s a file system in Pi. Developed by Philip Langdale, πfs takes one of the most important constants in mathematics to simple, compressed file storage. Πfs applies a disjunctive sequence to files, converting all files into metadata stored in a metadata directory. It’s a data-free file system for the metadata-driven world.

#2: Realm
Realm is a mobile database that runs directly inside phones, tablets or wearables. The repository holds iOS and OS X, the source code for both Swift and Objective-C. Realm data is directly exposed as objects and queryable by code, sporting an API with just three common classes (Objects, Arrays and Realms) and one utility class (Migrations).

#3: XDomain
Created by Jaime Pillora, XDomain is a pure JavaScript CORS alternative. No server configuration required; just add a proxy.html on the domain you wish to communicate with. This library utilizes XHook to hook all XHR, so XDomain will work seamlessly with any library.

(Don’t know what CORS is? We’ve got you covered.)

#4: Breach
Breach is a Web app running in its own process. The modular-everything browser allows construction of a custom experience using modules and custom JavaScript and CSS coding to create features with an open-source stack. Its tagline is “A browser for the HTML5 era.”

#5: Papa Parse
Papa Parse is a CSV-delimited text parser that can handle large files and malformed output. Developed by Matt Holt, Papa Parse directly parses CSV files, reverse-coverts JSON to CSV, streams large files via HTTP and auto-detects the delimiter.