The long and short of things is that my manager has me working on a project that has the most limited time scale I've ever seen. The timeline was given by the client, not determined by the project.
He wants a full fledged enterprise level app in just under 3 months that can host 10k plus users. I am the only dev working on it and although I've approached my manager about needing help he hasn't been receptive. I've gone over with him several times that I don't believe I will be able to make the deadline and his response to this has been to cut every possible corner I can. I have written 0 tests and much of, if not most of, any user input isn't undergoing any validation. I'm honestly writing code so quickly that I don't have a lot of time to think about architecture either.
He has stated that the company we are building the program for has a demo scheduled with their board of directors and that the deadline absolutely can't be extended and must be met. I'm incredibly nervous that I'm writing code which is introducing long term bugs that will be hard to track down and fix. To say this is putting a lot of worry on my place in the company is understating it.
I've read a lot of questions about how missing deadlines is very common in the software industry and I wondered how other devs go about preparing someone senior to them for that news without getting fired themselves, especially if that person isn't a technical person?