Finance and accounting decision

Gusto

A capable developer can build a limited payroll runner and payslip generator (useful for small single-state needs), but reproducing Gusto's full product — tax filing guarantees, licensed benefits brokerage, multi-state compliance, and enterprise-grade reliability — is expensive and operationally risky, so many teams should keep paying for the service.

Visit website
You pay

$35/mo

$420/yr

Per seat. Read off the official pricing page.

You’d pay instead

$100one-off80 h to build

$50/mo10 h/mo upkeep

On cash alone, building overtakes the subscription at 2 seats.

Open-source builds that already do this

Every project below is open source and already does this job today. Fork one, self-host it, or take the parts you need - the build prompt further down assumes an empty file, and this is the shortcut past that. Licences differ; check the one on each card before you ship. All Gusto alternatives, with the arithmetic →

What a replacement has to do

  • Compute payroll, withhold and file taxes, send payments to employees/contractors, and produce pay stubs and compliance filings.

What it still won’t have

  • licensed-broker health benefits administration and broker support
  • guaranteed tax filings and backed compliance services
  • access to Gusto's integrations and partner network
  • dedicated support and account advisory
  • scale-tested payroll infrastructure and uptime guarantees

What remains hard

  • Brand trustJoin 500,000+ small and medium-sized businesses that take care of their people with Gusto.
Read the build prompt

First-year cost

Keep paying

Paying is—cheaper in year one.

On cash alone, building overtakes the subscription at 2 seats.

Paid seatsseats

Money you would actually spend

Keep paying
—

Subscription price × seats × 12

Build it
—

AI build —APIs + hosting —

Time you would spend

—

—

What you would spend

What we assumed

The verdict above measures whether you could build it. This one is only about money.

Runnable build prompt

Not run yet
Build a self-hosted payroll web app using Django (Python) + Postgres + React. Implement: employee/contractor CRUD, payroll run engine (gross-to-net with configurable deductions and tax tables for one US state), time-off and timesheet sync, ACH payment integration stub (callable service layer to plug in Plaid/Stripe Treasury later), PDF paystub and 1099/W-2 generator, admin UI to run and approve payroll, and background job processing with Celery. Out of scope: multi-state tax rules, certified tax filing, brokered benefits, and EOR. Include error handling, logging, unit tests for payroll calculations, and an integration test covering a full payroll run producing paystubs and a payment request.
How we checked5 sources · 3/3 runs agreed · evidence score 67

How the score was reached

  • Partly verdict base52
  • An open-source build was found+5
  • 5 cited sources+3
  • Price verified on pricing page+3
  • 3/3 assessment runs agreed+4
  • Evidence score67

The base comes from the verdict. Everything under it is a check that either happened or did not, and each one is a fact frozen in this record rather than a judgement made at render time - so the same evidence always produces the same number.

How scoring works →

Integrity checks

What held up, and what did not.

✓ Price read off the page✓ 3 independent runs, one answer✓ Citations limited to fetched pages! 1 moat quoted from the page