Full-Stack Web Engineering & SaaS MVPs

Custom web applications engineered for speed, reliability, and growth.

From first-generation SaaS prototypes to high-volume B2B client portals, we build modular web applications with clean TypeScript architecture, automated testing, and zero technical bloat.

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TL;DR / Executive Business Summary

The Challenge

Founders and product leaders struggle with agencies delivering slow, unmaintainable codebases with unpredictable hourly invoices and missed deadlines.

The Fix

FixrWeb delivers modular full-stack applications using Astro 5, React Islands, Bun, and PostgreSQL on fixed-price milestones with weekly releases.

Business Results

4-week SaaS MVP launch, sub-second page interactions, 100% source code ownership, and fixed budgets.

Application Types We Build

Custom software tailored to your business model

SaaS MVP in 4 Weeks

Validate your software idea in market quickly. We build functional SaaS prototypes with authentication, database models, Stripe billing, and user onboarding.

✓ Auth0, Supabase, or custom JWT authentication
✓ Stripe Checkout, Customer Portal & Webhooks
✓ Transactional email with SendGrid or Postmark

B2B Client & Customer Portals

Provide your clients with a secure digital headquarters. Share deliverables, handle contract sign-offs, collect project briefs, and manage billing in one place.

✓ Multi-tenant data isolation
✓ Secure file uploads to AWS S3 or Cloudflare R2
✓ Role-based permissions for client teams

Full-Stack Web Applications

Scalable custom software with complex business logic. Built with modern component architecture to keep page responses fast under high concurrent traffic.

✓ Astro 5 SSR & React Islands architecture
✓ PostgreSQL with Prisma or Drizzle ORM
✓ Sub-100ms API response latency

Web App Modernization & Refactoring

Rebuild sluggish legacy codebases into modern TypeScript applications. We untangle technical debt and improve maintainability without disrupting current users.

✓ Zero-downtime database migrations
✓ Automated end-to-end Playwright tests
✓ Modular API and microservice separation

Modern Engineering Stack

Battle-tested technologies chosen for speed and longevity

We use modern, stable open-source frameworks with zero vendor lock-in.

Frontend

Astro 5 & React

Sub-second page transitions

Runtime

Bun & Node.js

Fast execution and low RAM

Language

TypeScript

Strict end-to-end type safety

Database

PostgreSQL

Reliable relational data

Billing

Stripe API

Subscriptions & invoices

Security

Edge WAF

Cloudflare Enterprise rules

Frequently Asked Questions

Questions about custom application development

How fast can you build and launch a functional SaaS MVP?

We typically deliver a production-ready SaaS MVP in 4 weeks under a fixed-scope milestone agreement. This includes user authentication, database architecture, billing integration with Stripe, core product workflows, and automated transactional emails.

What technology stack do you use for custom web applications?

We primarily build with Astro 5 Server-Side Rendering (SSR) or React, TypeScript, Bun or Node.js backend services, PostgreSQL for relational data, Redis for caching, and Tailwind CSS for responsive styling. We choose tools that maximize page speed and long-term maintainability.

Do you offer fixed-price contracts or hourly billing?

We work predominantly on fixed-price milestones with clearly defined acceptance criteria. You know exact timelines, deliverables, and total costs upfront without billing surprises.

What happens after the application is deployed?

We provide 30 days of post-launch warranty support to resolve any edge-case issues. We also offer ongoing maintenance retainers and dedicated managed cloud hosting.

How do you handle data security, authentication, and compliance?

We enforce strict security practices including encrypted environment secrets, parameterized SQL queries to prevent injection, bcrypt/Argon2 password hashing or OAuth2 providers, and edge Web Application Firewall (WAF) protection.

Have an application to build or modernize?

Let our lead architects review your project requirements. We provide a milestone-based scope and architectural specification within 48 hours.

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