[kalehrishi]

We[1] have been using inboxsdk to build integrations of products within gmail. Initially we had our own system to keep check of changes in gmail DOM structure and it was expensive to maintain such SDK. Streak has been doing great job of maintaining it. In 2017 gmail changed complete UI and inboxsdk seamlessly supported it with minor glitches. There are some tiny glitches on some days but those are fixed within few hours. Other open source option is gmail.js which is also a good alternative. However you have to write some automation test cases to keep check on breaking changes in gmail Dom

[1] https://www.vshsolutions.com/