Case study · B2B SaaS · Seed

SaaS MVP shipped in 14 days for a B2B SaaS startup

A seed-stage B2B SaaS founder needed a real, working product to put in front of their first customers, and had two weeks to do it. We delivered a deployed, multi-tenant MVP (auth, the core workflow, Stripe billing, and an admin view) in 14 working days.

Case studyB2B SaaS · Seed

B2B SaaS startup

14 working days · live MVP

Client

B2B SaaS startup

Engagement

Fast MVP · fixed scope, fixed deadline

Duration

14 working days

Team

2 senior engineers + 1 QA · 1 Hashorn PM

ServicesAI Software DevelopmentQuality Assurance

Outcomes at a glance

Time to live MVP

14 working days

Scope shipped

Core workflow + Stripe billing

Tested on

Critical paths, every push

Sprint timeline

How the engagement unfolded

  1. Day 1

    Brief, scope lock, kickoff

    One 90-minute call to lock the single core workflow, the stack, and the billing model. Killed every nice-to-have that would not help the first customers. By end of day: a one-page brief, a written cut list, and a risk register.

    One-page brief + cut list

  2. Day 2

    Multi-tenant foundation

    Auth, the tenant and core data model in Postgres, role-based access (owner and member), CI, and a deployed staging URL. A logged-in user lands on an empty state of the main view.

    Staging URL live · auth working

  3. Days 3-7

    The core workflow

    The one feature the SaaS is about, built end to end and persisted across sessions. Happy path first, then the edge cases (empty, maximum, invalid input). Demoable by day 7.

    Core workflow demoable

  4. Days 8-9

    Billing + admin

    Stripe subscriptions wired for the core plan, with the webhook handling made idempotent. A minimal internal admin view to inspect tenants and unblock support.

    First test subscription confirmed

  5. Days 10-11

    Polish + onboarding

    Error and loading states, mobile responsiveness, an accessibility pass, and a first-run experience that guides a new user to the core action.

    Onboarding flow live

  6. Days 12-13

    QA + bug bash

    Playwright across the critical paths, a structured QA bug bash, and triage to launch-blockers only. Everything non-blocking logged for v2.

    Critical-path specs green on CI

  7. Day 14

    Production launch

    Real domain with SSL, auth with real email delivery, monitoring and alerts wired, and the first real users onboarded.

    Live in production

Architecture

The stack we shipped on

Frontend

Server components for fast pages

  • Next.js 15
  • App Router
  • TypeScript
  • Tailwind

API

Same app; no separate API service for the MVP

  • Next.js Route Handlers
  • Zod
  • Idempotency keys

Data

  • PostgreSQL 16
  • Prisma
  • Row-level tenant isolation

Billing + auth

PCI scope kept out of the app

  • Stripe subscriptions
  • Managed auth (magic link)

Cloud

  • AWS
  • Vercel
  • GitHub Actions
  • CloudWatch

Risks we actively managed

  • Scope creep against a fixed deadline: a written cut list signed off on day one, with new ideas explicitly deferred to v2.
  • Multi-tenant data isolation: row-level tenant scoping enforced at the database layer, not just in application code.
  • Billing edge cases: Stripe webhooks made idempotent so a retried event never double-charges or double-provisions.
  • Launch stability: critical paths covered by Playwright and run on every push, so the launch build is the tested build.
Workflow

Tracked end-to-end in BuildOS.

Every meeting summary, requirement, sprint, task, and metric in this case study was rendered in BuildOS during the engagement. The customer's team had read-only access to the same workspace from week one, they saw Friday demos, weekly velocity, and AI-generated checklists without us sending status emails.

The challenge

A seed-stage B2B SaaS startup had a clear idea and a hard deadline. They needed a real, working product, not a prototype, in front of their first customers within two weeks, and they did not have an engineering team to build it.

Three constraints shaped the engagement:

  • It had to be real software. A clickable mockup would not survive contact with those first customers. The product had to let a real user sign up, do the core job, and have it persist.
  • The scope had to fit two weeks. That meant one core workflow for one user segment, with everything else explicitly deferred.
  • It had to be billable from day one of launch. The founder wanted to test willingness to pay immediately, not after a separate billing phase.

How we approached it

A two-engineer pod with a QA engineer and a Hashorn PM, run as a compressed version of our standard MVP sprint. The PM owned the day-by-day cadence and kept the cut list honest; the engineers paired so nothing was single-threaded. The single most important artifact of day one was the written cut list: everything we agreed not to build, so the two weeks could go entirely to the core workflow and the few things around it that a first customer genuinely needs.

We locked the architecture on day one and did not revisit it. A mainstream stack (Next.js, Postgres, Prisma, Stripe) meant zero time lost to tooling and a codebase the client could hand to future hires without a translation layer.

What we shipped

Days 1 to 2, foundation. Scope lock, the multi-tenant data model, auth, role-based access, and a deployed staging URL. A logged-in user could reach an empty version of the core view by end of day two.

Days 3 to 7, the core workflow. The feature the product exists for, built end to end and persisted, with the edge cases handled. Demoable by day seven.

Days 8 to 9, billing and admin. Stripe subscriptions for the core plan with idempotent webhooks, and a minimal internal admin view so support was not blind on launch day.

Days 10 to 11, polish and onboarding. Error and loading states, mobile, accessibility, and a first-run experience that walked a new user to the core action.

Days 12 to 14, QA and launch. A structured bug bash, Playwright on the critical paths, and a real production deploy with monitoring. The first real users were onboarded on day fourteen.

The outcome

  • A live, deployed SaaS MVP in 14 working days, on a real domain: auth, the core workflow, Stripe billing, and a minimal admin view.
  • Tests on the critical paths and monitoring wired before launch, so the founder could onboard real users with confidence.
  • A clean, mainstream codebase the team owns, with a prioritized v2 backlog built from the first week of real usage.

What we'd repeat

The discipline that made the deadline was the cut list. Every time scope threatened the two weeks, we cut from the bottom of the priority list rather than slipping the date, and the product was better for it. The other lesson was keeping billing minimal: one plan, wired cleanly, was enough to start testing willingness to pay without building a billing system the company did not yet need.

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