Just share my experience on writing a custom client apps for PushBullet, no code sharing, but just ways how to achieve it.
Recently I just started using PushBullet and I found it is useful and wonderful for personal use. PushBullet is a service allows sharing content (note, link, address) across devices (desktop, mobile, browser). You can add own devices, contacts, then you can share content from one device to another. Say I found an interesting link on iPhone, I can open PushBullet iPhone Apps and share to my Google Chrome. Google Chrome extension can be installed such that a desktop notification can be triggered whenever new PushBullet messages come in. It is free service, so, very good.
But I really really disappointed as currently no feature to clear all the messages, I can only delete one by one either from the desktop website or through PushBullet iPhone Apps. So I decided to write my own PushBullet client apps to get rid of this. Very easy, just less than 30 minutes, to write a perfect, no bugs, quite good user experience (just for my own use, I am technical person, so not need so beautiful).
First, I downloaded a PHP library that interact with PushBullet. OK, I also can use Node.JS but due to some reason PHP is more comfortable for me. I may also able to use iPhone Library but, I had another use case that need server side. Say my other Node.JS apps found some links and need to notify my PushBullet, they can call my PHP API to send PushBullet. I developed many many small apps, one apps do one thing, all for my personal use. OK, next.
The PHP API did very simple thing, register device identifier (from PushBullet) createDevice, push note (pushNote), push link (pushLink), delete the pushes (deletePush), internal database to store the pushes message identifier.
After integrate PushBullet into my personal apps, looking forward it will be able to increase my productivity on works.