I just designed, developed, and deployed my own budgeting app, dailybudget.cc, which allows me to automate my budgeting the way I have always done it, in a way that I could never fully capture with other budgeting apps, such as Mint, EveryDollar, or YNAB. I spent 4 years from the time I first had the idea to the time I actually sat down to design it and start development. During this time I evaluated many other budgeting app solutions, and had even architected a prototype that I never ended up using. But boy, have technologies come much further in 4 years.
Though my first prototype used Java and Tomcat, I completely abandoned those 4 years later in favor of Node.js technologies, which I have found are equally as stable, more flexible (for better or for worse), and capable of significantly more rapid development. Since what I have deployed now is in beta and is primarily for limited user use, I favored rapid development over slower development where I would write more automated unit tests. I chose to build the app as a HTML5 web application (rather than native iOS or Android, for now), and I used a separated API backend/Web frontend model. My target platform for use with the app is mobile handheld touch devices, though it can work on any laptop or desktop with a touchscreen. Given these design targets, many of the technologies I chose were because of familiarity with them as well as a strong online community, and some technologies I chose that I had to learn anew, because they appeared to fit my needs.
My entire app runs on a #lenovo IdeaCentre desktop on my home network, on which I have installed Ubuntu 18.04. Ubuntu is something I have switched to after a long time of use and familiarity with RedHat Enterprise Linux and CentOS, because the online support for Ubuntu is now tremendous, and there is so much documentation and examples online of how to configure and use Ubuntu; not to mention I have not been thrilled with the direction new releases of CentOS. Ubuntu is also a good environment for development - it is so easy to follow the many online examples. Lastly, I may migrate my app and configuration to Amazon AWS, which also uses Ubuntu for its EC2 Linux VMs, so having Ubuntu now is helpful for that prospect.
The API backend uses Node.js, with #HapiJS as the API server framework and MySQL as my persistence database. HapiJS is something I have had familiarity with and is just a phenomenal framework to plug into and configure, especially if you use it for a route-based API. #Mysql has a great online community. I could've used PostgreSQL too, but I am more familiar with MySQL. Also, if I migrate to Amazon AWS, Amazon's RDS uses MySQL. I use npm as a one-stop-shop package manager and environment manager.
I use nginx as my web server and have the API running behind a reverse proxy, and all of the web frontent content hosted as static content.
I use the plaid API to sync my bank transactions to my database. This is another fantastic framework (though not free beyond development use) that it turns out is extremely easy to use for the complex job that it solves.