# Case Studies: How We Build Real Products
> App369 case studies: how we build Flutter and Firebase products, starting with Workspace369, with the real stack, architecture and lessons learned.
Canonical: https://app369.com/case-studies/
How we design, build and run real software, with the stack, the architecture and the lessons. Every fact on these pages is checkable. Client numbers are either public, like App Store ratings, or given to us by the client.
## Browse All Case Studies
[SaaS / Business software**Workspace369: a Flutter and Firebase SaaS for client work**
An all-in-one workspace for freelancers and small service businesses: CRM, proposals, invoicing and payments, scheduling, a shared email/SMS/voice inbox, accounting and AI, in one Flutter app on iOS and the web. - Flutter - Dart - Firebase - +7 more **Read Case Study **](https://app369.com/case-studies/workspace369/) [Field service software / Contractor CRM**QuoteIQ: a contractor CRM in Flutter, Nuxt and Firebase**
A CRM for home service contractors: quotes, scheduling, invoices and payments, customer messaging and AI automations, on iOS, Android and the web. On the App Store since September 2022, with 3,400+ ratings and a 4.7 average. - Flutter - Dart - Nuxt - +4 more **Read Case Study **](https://app369.com/case-studies/quoteiq/) [Consumer / Music**3693: a private music app in Flutter and Firebase**
A private music app built with Flutter: search, a now-playing screen with lyrics, a queue, playlists, liked songs, a cloud library, listening stats and light and dark themes, on a typed Firebase backend. - Flutter - Dart - just_audio - +6 more **Read Case Study **](https://app369.com/case-studies/3693-music-app/) [AI integration / Open source**saas-mcp-connector: a safe MCP server for a SaaS API**
An MCP server that lets Claude Desktop, Claude Code and other MCP clients use a SaaS product's API safely. Every call is scoped to one user's workspace, writes need explicit confirmation, and the HTTP transport is rate limited. - TypeScript - Node.js - MCP - +3 more **Read Case Study **](https://app369.com/case-studies/saas-mcp-connector/)
Fiverr buyers
## From Fiverr buyers, in their own words
Three buyers who came back again and again, told through their public reviews on [Simon’s Fiverr profile (opens in a new tab)](https://www.fiverr.com/szymondziak). Quotes are word for word. Buyers are shown by first name and country only.
- Mark, United States ### [Sixteen five-star reviews from one buyer: mobile apps, app design and a Shopify store](https://app369.com/case-studies/fiverr/mobile-apps-and-a-shopify-store-for-one-buyer/) Mark’s first Fiverr review of Simon, in October 2020, is for a mobile app. Over the next 21 months he left 15 more, for more app development, app design, a Shopify store and custom orders. All 16 are five stars.
- A buyer in the United States ### [A large custom app build, delivered on the back end and the front end](https://app369.com/case-studies/fiverr/large-custom-app-build/) A buyer in the United States first reviewed Simon in February 2022, then reviewed a large app build four times between April and August. All five reviews are five stars.
- Rachel, Canada ### [Four Shopify reviews in under three months, then an app](https://app369.com/case-studies/fiverr/shopify-store-repeat-orders/) Rachel left her first review of Simon’s Shopify work in November 2020 and her second nine days later. Her third came in December, a fourth Shopify review in February 2021, and her fifth, in March 2021, is for an app. All five are five stars.
## **Want something similar at a fixed price?**
Fixed scope, fixed price, paid upfront. The work happens in writing; no call needed.
- [**Web App MVP Sprint**from $6,000A scoped web app MVP in Vue/Nuxt or React, with a fixed quote after a $450 written scoping.](https://app369.com/fixed-price/web-app-mvp/)
- [**App Fix Ticket**from $450One reproducible bug in an existing mobile or web app, diagnosed and fixed.](https://app369.com/fixed-price/flutter-firebase-bug-fix/)
- [**Monthly Dev Subscription**from $1,495/monthOne development request at a time, most back in about 2 business days. Pause or cancel anytime.](https://app369.com/fixed-price/monthly-dev-subscription/)
****Simon Dziak****Founder and head developer
## **Get a personalized assessment by email**
Submit your project details and Simon replies by email with a personalized assessment, usually within one business day.
[**Get in touch **→](https://app369.com/contact/) [**Instant quote**](https://app369.com/instant-quote/)
Prefer a call? [Consultations](https://app369.com/service/consultations/) are $100 per 15 minutes, paid upfront.