This is a Software as a Service (SaaS) website that provides a portfolio management tool for people investing in ETFs.
If you don't know what a SaaS website is, it is basically a software application that runs on the web that you pay a subscriptions to access. Examples include QuickBooks Online, Google Apps, and Office 365.
My client had developed an Excel sheet which he used to manage ETF portfolios for friends and family.
He then came up with the idea to make the Excel sheet into a SaaS website.
He first worked with a company which had him specify the functionality. However he got fed up when it did not seem they were ever going to get out of writing specification and actually build the website.
That's when he came to me.
I took the specifications he had developed with the other company and used it as reference to build the website. I had a more agile approach when it came to development, though I also used waterfall. My hybrid (agile + waterfall) approach involved specifying enough for a sprint I could handle alone, since I was the only developer in the project.
This worked well and we had a Minimum Viable Product within two months.