William Cunningham

About Me

I’m a CPA, a small business mentor, and a business app maker. Right now I’m building Dattuh, bookkeeping tools for small businesses. I’m building it with AI coding agents.

This site is my working notebook. I write about what I’m building, what I’m learning along the way, and the business ideas behind it all.

What I’m building: Dattuh

Dattuh gets a small business’s sales and payment data into QuickBooks Online, and gets it right.

Subscribing to an accounting system is the easy part. The hard part is getting the data from Square, Shopify, Stripe, Squarespace, Eventbrite and the rest into your books, then trusting the numbers once they’re there. Most owners end up paying someone, often themselves, to type and reconcile it by hand.

Dattuh connects those platforms to QuickBooks and maps every field the way your business uses it. It follows each transaction from the sale through to the processor fee and the bank deposit, and it takes care of recurring bookkeeping tasks so the books stay current without the busywork.

Dattuh isn’t a new idea for me. For years I built a version of it in Excel and VBA for the micro-businesses I mentored. Dattuh is that tool rebuilt properly, so any small business can use it.

How I build: a maker working with AI agents

I’m a maker, probably not a coder.

I started writing macros when Lotus 1-2-3 was a thing, then moved to Excel and Visual Basic for Applications (VBA). I’ve spent thousands of hours on data integrations, transaction automation, reconciliations, budgeting and forecasting. I made my share of mistakes, and I saved businesses a lot of money.

When I set out to turn my VBA integration tool into a real web application, I started learning Ruby on Rails, a framework designed for the one-person team. Learning Rails taught me how good software is put together. My coding notes are what’s left of that learning.

Today, Dattuh is built with AI agents, mainly Claude Code. The work splits along what each of us is good at:

  • I bring the accounting and the judgement. I decide what Dattuh should do, how transactions should land in QuickBooks, and what “correct” means for a small business’s books.
  • The agent writes most of the code. It works from written plans, follows the project’s conventions, and runs the tests.
  • I review, test, and decide. Nothing ships until I’ve checked that it does what a bookkeeper would expect.

Working this way lets one CPA build and run a real SaaS application. I’ll write here about what works, what doesn’t, and what I’m learning about building software with agents.

Where I come from

I’m named after my two grandfathers, William Cunningham and Andrew Shaw. One was born six years after the American Civil War. Both were farmers, which is probably one reason I enjoy working with small businesses.

I spent most of my career in financial and accounting roles in the television industry. I’m a CPA licensed in the State of Rhode Island. Over the past several years I’ve volunteered hundreds of hours mentoring small business owners.

I’ve struggled most of my life to name my purpose. Looking back, every chunk of code I wrote to solve a business problem was a breadcrumb pointing the same way. Dattuh is where those breadcrumbs led.

Puzzles

During the pandemic, jigsaw puzzles became a family hobby. I enjoy the problem-solving, the focus it takes, and the satisfaction when the last piece goes in. Then the pieces go back in the box and you start a new one.

Building a business, or a piece of software, is a lot like a puzzle. You start with a pile of pieces, and over time an idea becomes something real. Most days you focus on the next piece. When you reach a milestone, you celebrate, then get back to building.

What you’ll find here

  • Building Dattuh: progress, decisions, and lessons from building software with AI agents.
  • Other projects: whatever else I’m making.
  • Business models and principles: ideas I use when mentoring micro-business owners.
  • Accounting topics how-tos on creating meaningful accounting data for your business focusing mainly on QuickBooks Online.

You can reach me by email or on LinkedIn.

Bill Cunningham