A journeyman plumber needed to send invoices. Every platform wanted $30/month for features he'd never touch. I built one inside the tools he already had open.
A friend — journeyman plumber, licensed contractor — needed a way to send invoices. He'd been writing them by hand or using Word templates. Every invoicing platform he tried charged $20-30/month for features like team management, inventory tracking, and CRM pipelines. He needed one thing: generate a professional invoice, track it, and send it.
The tools weren't built for people like him. They were built for companies that had outgrown the problem he was trying to solve for the first time.
He already had Google Workspace through his email. The solution had to live there — no new accounts, no new passwords, no new monthly charges. Google Sheets as the ledger, Google Docs as the invoice template, Apps Script as the glue.
This constraint eliminated entire categories of complexity. No server, no database, no deployment pipeline. The entire tool runs inside Google's infrastructure with zero hosting cost.
SoloBill is a complete invoicing system that runs inside Google Sheets. The sidebar UI handles everything: client management, line-item entry with live calculation, tax computation, and one-click invoice generation.
Line items calculate dynamically — quantity × rate updates the subtotal in real time. Tax is computed at the row level. The total reflects everything as you type. When you click "Generate Invoice," Apps Script builds a formatted Google Doc from the data and exports it as a PDF.
"The best tool for a one-person operation is the one that doesn't require a second person to manage."
The Sheet has dedicated tabs: Invoices (the ledger), Clients (contact details), and Settings (business info, tax rate, invoice numbering). The sidebar reads and writes to these tabs through Apps Script.
All line-item math happens client-side for instant feedback. When saved, the complete invoice data writes to the Invoices tab as a single row with a JSON-serialized line items field. This keeps the ledger flat and queryable while supporting arbitrary line item counts.
The core invoicing flow is complete and functional. Create, calculate, generate, export. The Report tab (revenue by month, outstanding invoices) and automated email sending are next.
SoloBill is also a candidate for integration into FieldKit as a vertical configuration — the same engine, tuned for contractor invoicing.