Company merger - impossible 3-months rewrite
It was a fun time, our company acquired two other companies and we were told that we have 3 months to integrate all the products into a single, unified platform. So you would sign in and could use one, two, or three products in any configuration seamlessly. We estimated the effort for around 1 year of work and we got 3 months to deliver it. Short version - we managed to do so. How we did it is a sum of many different things - mostly having very engaged members within our team. This is how it went down:
1-2 people doing the groundwork - to cut down the communication cost up two people were responsible for preparing the ground for other teams. By ground, I mean building the core structure of the application and/or modifying existing application so it would communicate over API with other app(s) and whatnot
after groundwork was done different teams were taking over the work - we defined scope for around 2 months with a ~1-month buffer. The scope was cut down to the bare minimum but it was really tight. The upside here - it was pretty clearly defined so not like a ton of questions appeared during the development.
we outsourced the landing part to another company - the outcome wasn’t great, but welp - we had something online (later maintenance was a true PITA, but that’s a different story about outsourcing stuff)
I think the important part here was that I and the technical cofounder knew the app very well and we were able to spot potential roadblocks (at least most of them) and have a rather clear vision of how the whole thing would work from top to bottom and we were able to document that vision clearly as JIRA tasks.