How to build something that's yours on the side: 5 steps for the first employee doing founder-level work
You hold the vision, the complaints, and the onboarding in the same hour. Here's how to point that range at something small that belongs to you, without quitting and without crossing a line.
Reviewed for business accuracy by Kathryn Finney, serial entrepreneur, investor in 100+ companies, and author of Build the Damn Thing.
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Nothing on this page is legal, tax, or financial advice. The lines below are ones you fill in yourself. How this inventory works.
The Co-Builder
Every step on this page, walked through, so you can test one idea of your own and land a first paying customer on the side.
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What you need to start
The guide's own cheat sheet. The how for each one is inside.
What you already have: the range to run a company, built on someone else's payroll and yours to keep.
What the five steps do: read your real position, think like an owner, test a small idea on the side, validate it at a real price, and land your first paying customer.
The rule that keeps you safe: off company time, off company devices, and outside your employer's business, checked against your own agreements.
The pace: a few hours a week, built to reach a tested idea and a first paying customer inside about 90 days.
Your ownership and leverage inventory
This guide is about a decision, not a business's cost model, so there's no startup number to quote you. Before you decide anything, sort what's actually yours from what's tied to this one company. The left column travels with you. The right column is what a stay-or-go decision really turns on.
| Yours to keep, no matter what happens | Not yours, or at risk |
|---|---|
| Three skills you've built here that travel with you____ | Unvested equity (amount and vest date)____ |
| Relationships that are yours, not the company's____ | Vested equity, realistic value after dilution and preferences____ |
| Your reputation and track record, in one line____ | What the company owns that you can't take (IP, accounts, lists)____ |
| What you've learned about actually building a company____ |
This is a self-assessment you fill in yourself, not a valuation, and not a figure BUILD supplies or verifies. Every line comes from your own documents: your grant paperwork, your vesting schedule, your cap table conversations, and your honest read of what you've built here.
The left column is your real net worth as a Builder, because it's portable and no cap table controls it. The right column is what a stay-or-go decision turns on, so know it cold. None of this is legal, tax, or financial advice.
Decide from options, not fear
The ownership and leverage inventory, the owner's-language table, the five-person validation worksheet, and the 90-day parallel plan.
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Where these numbers come from
Every line on this page is one you fill in yourself. See how this inventory works. Kathryn wrote Build the Damn Thing for Builders in exactly this spot, and this guide is the side-of-the-desk version of that method.
- BUILD toolExit calculator: the monthly income that replaces a paycheck
- BUILD articleRegister your business, state by state
- SBAU.S. Small Business Administration: Register your business
Employment agreements, IP assignments, and government rules all vary and can change. Read your own documents, confirm current requirements with the appropriate agency, and get an employment attorney's read where you're unsure.
Related resources
The monthly income your own thing needs to replace a paycheck.
Eight questions to find out which kind of Builder you are.
Which entity to pick, how to file, and where the SBA tool lives.
Build a realistic first-year number for your side idea.
Every free planning tool in one place.
Guides, articles, and templates for Builders getting to a first sale.
Frequently asked questions
Am I allowed to build something on the side while I'm still employed?
It depends entirely on your own employment agreement, IP assignment, non-compete, and moonlighting policy, so read all four before you start. The guide's rule is simple: off company time, off company devices, and outside your employer's business. Where you're unsure, get an employment attorney's read on your specific documents.
What if I'm worried this crosses a line with my employer?
Re-read your employment agreement and IP assignment, then pick an idea that's clearly outside your employer's lane. Keep everything on your own time and your own devices. If you're still unsure after reading your documents, get professional legal advice before you build or sell anything.
How much of my equity is actually mine to count on?
Separate what travels with you no matter what happens, which is your skills, your relationships, and your reputation, from what's tied to the company and at risk, which is your unvested equity and the realistic value of your vested equity after dilution and liquidation preferences. The guide walks you through both sides so you're working from real numbers.
What if my company looks like it's struggling?
That's exactly when knowing your vested-equity math matters most, and it's when keeping your own side test moving matters most too. If you know what's actually yours and you've got one small idea in motion, a bad outcome at the company isn't a dead end for you.
Is $9.99 really all it costs?
Yes, one time, delivered instantly, and it's yours to keep. The regular price is $19.99, and $9.99 is a limited-time launch price.