Personal software · Custom internal tools
1099 Tax Planner
A self-hosted app I built to track contractor income, expenses, estimated taxes, and payments in one place.
Implemented application source · Personal development project
I wanted to see my income and estimated tax obligations together without uploading my financial records to another service.
Multiple sources, business use, and deductible amounts.
Taxable income, quarterly periods, paid amounts, and remaining estimates.
Projected earnings after tax, summaries, and portable exports.
A tool I needed myself.
The project grew out of my need to understand self-employed income without sending sensitive financial records to another consumer SaaS platform. It connects my Information Systems and accounting background with hands-on software development.
One view of a fragmented workflow.
Gross income alone does not show what a contractor can actually keep. Income from multiple sources, business purchases, estimated obligations, and payments already made need to be modeled together without confusing an estimate with a final tax result.
Product direction and engineering review.
I defined the requirements from my own workflow, used AI-assisted coding to develop the application, and reviewed the implementation. I worked on the data model, dashboard, calculations, API, and self-hosted setup. This is a software project; I don’t offer accounting services.
Implemented architecture.
The inspected source includes a React / TypeScript frontend built with Vite, a Node / Express API, a PostgreSQL schema managed with Prisma, and a shared TypeScript calculation module with unit-test source. A local authentication flow and report endpoints are present. These are source-verified components, not a claim that this review validated a live deployment.
From entries to a useful financial picture.
- Track multiple income sources, gross income, expenses, business-use percentages, and calculated deductible amounts.
- Estimate taxable income, self-employment and income taxes, net earnings after estimates, and remaining estimated liability after recorded payments.
- Display quarterly periods, due dates, recommended payments, and actual payments made.
- Explore potential purchase deductions and credit questions, with uncertainty kept explicit.
- Export income, expense, quarterly, and accountant-oriented CSV summaries, plus JSON backup data.
The important boundary: estimates are not advice.
The application uses simplified, configurable planning assumptions. A calculation can be internally consistent while still being unsuitable for a particular taxpayer. Rates, rules, eligibility, and results require review by a qualified tax professional. The application does not file returns or guarantee deductions, credits, or tax savings.
Next engineering priorities.
Validate current deployment and backup/restore behavior, expand calculation edge-case coverage, and keep estimation assumptions visible alongside reports. No real financial data, deployment addresses, or private screenshots are included here.
What this means for a business.
Similar tools can help a business collect records, produce reports, or reduce repeated data entry. The first step is understanding the task and who will maintain the tool.
Explore custom business tools & automation ↗This project demonstrates software engineering, not CPA, tax preparation, legal, or financial advisory services.
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This is an example of my experience, not an endorsement from an independent client. If you need similar help, take a look at my services or send me a description of the problem.