Web App Development
Fast Web App Development
3-7 business days from brief to production deployment. Not a prototype, not a staging environment — a real working web app that users can sign up for, pay for, and use today.
Why Speed Is a Product Strategy, Not Just a Nice-to-Have
The value of an MVP is the learning it generates, not the code itself. A 3-month development cycle for a product that turns out to be wrong is an expensive way to learn. A 5-day build for the same product means you validate the core hypothesis for a fraction of the cost, with 11 weeks left in the quarter to iterate or pivot. Speed isn't about cutting corners — it's about shortening the feedback loop between your idea and your first paying customer.
Our fast development workflow, which we call vibe coding, is built on two compounding advantages. First, AI-assisted scaffolding handles the patterns that are the same on every project: auth flows, API routes, form validation, database connection setup. These used to take days — now they take hours. Second, our pre-built Next.js starter already has auth, payments, email, and deployment wired up and tested. You're not paying for the 50th time we configure Supabase; you're paying for the first time we configure your specific business logic.
Parallel workstreams eliminate the waterfall delays that inflate timelines. Traditional agencies wait for design to finish before starting development. We start building the unblocked infrastructure — database schema, auth, deployment pipeline — while design is still in progress on the complex screens. By the time the design is done, the infrastructure is already running. We're not adding risky parallelism; we're removing artificial sequential dependencies.
Our Approach to Fast web app development
Every project follows our 4-step vibe-coding process — AI handles the boilerplate, senior engineers handle the craft. From idea to live product in 3–7 days for MVPs.
Day 0: Scope Lock
We run a 60-minute scoping session on the day you commit. We define the exact screens, data model, and acceptance criteria for the MVP. By end of day, both parties have a written scope document — nothing starts until scope is locked.
Days 1-2: Infrastructure & Core Logic
Database schema, migrations, Supabase auth configuration, Stripe setup, and the server-side business logic for the core feature. The app can be created and data can be read/written before a single UI screen is designed.
Days 2-4: UI Screens & Integration
Screen-by-screen implementation in Next.js with Tailwind CSS. Server components handle data fetching; client components handle interactive state. Each screen is deployed to the staging URL as it's completed — you see progress daily.
Days 5-7: QA, Polish & Launch
Cross-browser and mobile testing against acceptance criteria, edge case handling, error states, empty states, loading states. Production deployment to Vercel with your custom domain. Launch day is day 5-7, not day 60-90.
What You Get
Every fast web app development engagement includes these deliverables — scoped before we start, delivered before we invoice.
- Scoped and locked requirements document on day 0
- PostgreSQL schema with seed data for local development
- Authentication: email/password + Google OAuth
- Core application screens: responsive, tested on Chrome/Safari/Firefox
- Server-side business logic with full TypeScript types
- Stripe payment or subscription checkout (if scoped)
- Staging environment updated daily during build
- Production deployment on Vercel with custom domain and SSL
- Sentry error monitoring configured and alerting to your inbox
- 2-week post-launch bug-fix support window
Tech Stack We Use
Speed is built into our stack choices. Next.js 15 server components eliminate client-side loading states for initial renders. Supabase removes weeks of backend infrastructure setup. Our pre-built starter already has auth, migrations, Stripe, Resend email, and Vercel deployment working on day 0. TypeScript and Zod validation catch bugs at compile time rather than in production. Vercel deploys every git push in under 30 seconds. Every tool in our stack is chosen partly because it makes fast, safe iteration possible.
Case Study
SEO Pilot — Live in 5 Business Days
The SEO Pilot founders had a launch date locked to a conference appearance where they planned to demo the product. The conference was 8 business days away when they first contacted us. We ran the scoping session on day 0, locked the MVP scope (auth, research workspace, content editor, publishing queue, Stripe checkout), and started building on day 1. By day 3, the core workspace was functional on staging. By day 5, the full app was deployed to production with a custom domain. The founders had 3 days to run their own QA before the conference. They demoed a working product — not a prototype, not a mockup — to a room of potential customers.
Read full case studyPricing Transparency
Fast web app development starts at $5,000 for an MVP (3-5 screens, auth, core logic, production deployment). Full builds with more screens, complex workflows, and admin tooling run $15,000. Fixed-price means the scope and cost are locked before day 1 — the speed doesn't come at the cost of financial predictability.
MVP
From $5,000
3–7 business days
Full Build
From $15,000
2–4 weeks
All projects include full code ownership, two revision rounds, Vercel deployment, and one week of post-launch support. No hidden fees.
Frequently Asked Questions
Is a 3-7 day build actually production-quality or just a prototype?
Production quality. The app has real auth, real data persistence in PostgreSQL, real error handling, real Sentry monitoring, and is deployed to Vercel with HTTPS and a custom domain. It can handle real users signing up and paying on day 1 of launch.
What makes vibe coding different from just using AI to write code?
Vibe coding means AI generates the pattern-repetitive code — auth boilerplate, API route structure, form validation — while senior engineers own the architecture, review every AI output, write the business-critical logic, and catch the subtle bugs AI misses. It's AI as a scaffolding tool, not an unsupervised code generator.
How can you run design and development in parallel without rework?
We separate the work into parallel tracks: infrastructure (database, auth, deployment) and UI (screens that require finalized design). Infrastructure doesn't need design to start. We build infrastructure on day 1-2 and design simultaneously, then implement UI as each screen is designed. The tracks converge by day 4.
What if I need to change something mid-build?
Small clarifications (label text, field names, color choices) are handled immediately with no cost or timeline impact. Significant scope changes — adding a new screen, changing the data model — require a change order and may extend the timeline. We communicate this clearly and quickly.
Do you provide same-day support after launch?
During the 2-week post-launch support window we respond to bug reports within 4 business hours and deploy fixes the same day for critical issues. Non-critical issues are batched into a weekly release.
Can every type of web app be built in 3-7 days?
No. The 3-7 day window applies to well-scoped MVPs: 3-5 screens, one primary workflow, standard auth and payments. Complex platforms with multi-tenancy, SSO, large data integrations, or many user roles take 2-4 weeks for a full build. We're transparent about timelines in the scoping session.
What's the fastest you've ever launched a production web app?
3 business days for a tightly scoped internal tool. The record-breaker was a project with a locked data model, approved designs, and a founder who replied to every question within 10 minutes. Fast client communication is as important as fast engineering.
Ready to ship?
Stop Waiting 3 Months — Ship Your MVP This Week
Start Your ProjectOr reach us directly at hello@greta.agency
Written by the Greta Agency team · Last updated April 2025