There were many questions asking about recent experience with MongoDB. I have some recent experience so wanted to share with everyone. My background: 2007-201

There were many questions asking about recent experience with MongoDB. I have some recent experience so wanted to share with everyone. My background: 2007-2010: Used MySQL to run a social network for 50M+ users. Would send 2B messages on peak days. All powered by Mysql. 2015-2020: Used Mongo to power a top 5k site. Zero downtime and dataloss in 5 years. Used Postgres for internal non user facing database So I have familiarity with all of these databases at a decent scale. I am going to list pros and cons of each and why I would use. Again a tool is a tool. Just because I love a wrench, doesn't mean that I am going to use it instead of a hammer when I need to put some nails. MongoDB: They have come a long way since I started using them in 2012. If your use case is CRUD, you would be fine. There is still a lot of marketing fluff about sharding, multi document transactions etc which might not be fully reliable. I stay away from those things. But if you just use CRUD and you data can fit in a single db you are going to be fine at decent scale. Following are some reasons I prefer Mongodb. It's possible that Postgres/MySQL has some of them even though I couldn't find them: 1. I don't like to manage schema migrations. During development you constantly add columns and it's a pain to make sure that this column is added to the sql databases on development, testing, staging, prod etc. With mongo, you just add a column and you are done. 2. No downtime on migrations: You can change you server type or mongo version with zero downtime. Did that since 6 years. Couldn't figure out how to do that with postgres (even with Aurora). 3. If you data structure fits document and subdocument schema, mongo is really easy to use. I tried jsonb with postgres and didn't find it as easy to use at mongo. If you data fits this paradigm, you can essentially get atomicity for multiple updates because they are all in a single document. 4. The admin interface of MongoDB Atlas is really development friendly. You can easily add read only replicas. You can easily add replicas in different regions. I shudder at the thought of managing Postgres myself and even Amazon Aurora is not as easy to admin as Atlas. At this point I would consider Postgres only in the following case: If my data structure is like a non-tree graph. In that case I would expect to do multiple complex join and expect transaction consistency between tables. If I am building a financial product which directly handles money or money instruments (bank, stock trading) I would definitely not use mongo for that. Happy to answer followup questions.