Years ago, I was doing gigs on Fiverr. Mostly Excel work — macros, pivot tables, solver models. I had a profile and a handful of listings, and I’d written about that whole love/hate experience back in 2017 (short version: the clients who treat you like a vending machine are the price you pay for the ones who bring you genuinely interesting problems). One day, a genuinely interesting problem showed up.
A training company needed help scheduling their staff. Multiple clients, multiple courses, multiple instructors, limited hours, shared equipment, weird simultaneous constraints. Classic Operations Research territory. I said yes.
The part where the client changes his mind
Here is the thing about technical consulting that nobody warns you about: the hardest part isn’t the math. The hardest part is figuring out what the client actually wants. That takes time. It takes back-and-forth. It takes building something, showing it, watching the client’s face, and realizing they meant something different than what they said.
I spent real time on this one. I understood the problem. I built the model — in Excel, using a plugin called SolverStudio that lets you embed Python optimization code directly in a spreadsheet. I had it running. The solver was finding optimal schedules. It worked.
Then the client backed out.
(I am not bitter about this. Not even a little. It is, as I said, the price of the interesting problems.)
The trouble with this kind of work is that by the time you really understand what someone needs, you’ve already done most of the thinking. The model was in my head and in an Excel file. The client was gone, but the problem was still there, solved, sitting in a spreadsheet nobody would ever open.
Why I finished it anyway
I kept the file. I don’t know exactly why — maybe because throwing away a working optimization model felt wrong, the way it would feel wrong to throw away a tool you built by hand. It went into a folder on my computer with about twenty other models I’ve built over the years: vehicle routing, warehouse slotting, least-cost formulation, staff scheduling. Xlsm files, all of them. All working. All completely inaccessible to anyone who doesn’t have the exact same Excel setup I have.
That’s the part that started to bother me. Not the abandoned Fiverr job specifically, but the whole situation: I have twenty-plus years of Operations Research work sitting in Excel files that nobody can use but me. Models I built for real problems at Cargill, at Cessna Aircraft, at Textron Aviation. Models I built for fun, for clients, for consulting projects. And every single one of them requires SolverStudio, requires the right version of Python, requires someone to sit at my computer.
The FIRE angle here is real, by the way. When you don’t need the money — when you’ve already solved the financial problem — you can afford to finish things that don’t have a clear payoff. You can spend an afternoon turning a Fiverr ghost job into something that actually exists in the world. That’s a luxury, and I don’t take it for granted.
What I built
The staff scheduling model is now a web application. You go to a URL, you upload an Excel workbook with your scheduling data, you click a button, and it hands you back an optimized schedule as a downloadable CSV and an interactive pivot table. No SolverStudio. No Python installation. No nothing except a browser.
The app runs on a server in Oregon. It uses the same optimization logic I built for that Fiverr client years ago — the same mathematical structure, the same solver, the same constraints. It just doesn’t require you to be me to use it.
You can try it here: Staff Scheduler. There’s a sample workbook to download if you want to see the data format.
What’s coming in this series
This is the first post in a series about that conversion — from Excel model to deployed web app. The next posts cover the math behind the model (it’s a Mixed Integer Linear Program, which sounds intimidating and isn’t), three bugs we found during the conversion that would have stayed hidden in Excel forever, how the web app is structured, and how I deployed the whole thing for seven dollars a month.
The series is also about the bigger project: I have about twenty models in that folder. Staff scheduling is one. The plan is to work through them, one by one, turning each into something a person can actually use without calling me first. If you’ve got technical skills and more time than obligations, this is a reasonable thing to do with an afternoon.
More soon.
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