# A website for your business. Your mobile app for iOS and Android. > Explore App369's software development services: mobile app development, web development, UI/UX design, technical consulting and ongoing maintenance. Canonical: https://app369.com/service/ App369 builds both, plus the backend, payments and AI features behind them, for startups and small businesses, from Miami, Florida. **Under the hood:** Vue, Nuxt and React on the web; Flutter and Swift for iPhone and Android; Node.js, TypeScript and Firebase on Google Cloud behind them. AI implementation ## **AI that answers your leads and handles the repeat work** For clinics, law firms, agencies, SaaS teams and real estate offices: one channel or one workflow at a time, at a fixed price, in code and accounts you own. [

**AI Implementation**

Custom AI development for your business, one fixed-scope piece at a time: AI features and agents with a one-page spec and a scored eval run, integrations, all in accounts you own. - Custom AI - AI Features - Agents - EvalsLearn more](https://app369.com/service/ai-implementation/) [

**AI Receptionist**

Calls, chat and web forms answered 24/7, leads qualified and booked on your calendar, and a person brought in with a summary. Missed-call text back is its own fixed-price piece. - Answering - Booking - Missed-Call Text Back - Twilio Learn more](https://app369.com/service/ai-receptionist/) [

**AI Answering Service**

Calls answered day and night on your own number, the message taken or the appointment booked, and missed calls texted back. Built once at a fixed price instead of a plan sized by calls. - After Hours - Your Own Number - Messages - Twilio Learn more](https://app369.com/service/ai-answering-service/) [

**Speed to Lead**

Missed calls texted back, web form leads answered with a booking link, and every lead routed to the right person and logged in your CRM. - Missed-Call Text Back - Lead Routing - AI Follow-Up - Twilio Learn more](https://app369.com/service/speed-to-lead/) [

**AI Automation Services**

One repeated task at a time automated inside your own tools: lead intake, document extraction, email triage, syncs and reports, tested and logged. - Workflow Automation - Document Extraction - Email Triage - Integrations Learn more](https://app369.com/service/ai-automation-services/) [

**AI for Accountants**

An AI email assistant for accounting, tax and bookkeeping firms: client email labeled, routine replies saved as drafts, and nothing sent without a person. - Gmail - Microsoft 365 - Drafts Only - Fixed Price Learn more](https://app369.com/service/ai-for-accountants/) [

**Chatbot Development**

An AI chatbot for your website, your app or your staff that answers from your own pages and documents, built to link the page behind each answer and hand off to a person. - Website Chat - Help Assistants - Internal Knowledge - Hand-Off Learn more](https://app369.com/service/chatbot-development/) [

**AI Agent Development**

One AI feature or agent built in 10 business days from a spec you approve, with tools limited to approved actions and a scored eval run before handover. - AI Agents - LLM Features - Eval Sets - MCP Connectors Learn more](https://app369.com/service/hire-ai-agent-developer/) [

**AI Consulting**

Paid consultations on what to automate first, a written quote for the build, then a fixed-price build from the same developer. - Written Scope - Paid Consultations - Fixed Price Learn more](https://app369.com/service/ai-consulting/) Apps and platforms ## **Mobile apps, web apps and the backend behind them** The product itself: iPhone and Android apps, websites and SaaS, APIs and payments, design, search and the upkeep after launch. [

**Mobile App Development**

iOS and Android apps in Flutter or native Swift, from a first release to fixing an app that already has users. - iOS App Development - Android App Development - Flutter Cross-Platform Apps - App Store OptimizationLearn more](https://app369.com/service/mobile-apps/) [

**Web Development**

Web applications built with Vue.js and Nuxt, server-rendered for fast first loads. - Custom Web Applications - E-Commerce Platforms - Progressive Web Apps (PWA) - API Development Learn more](https://app369.com/service/web-apps/) [

**SaaS Development**

A first SaaS version in about 4 weeks from a signed quote, with Stripe subscriptions, sign-in and roles, and the integrations your customers ask for. - Web App MVP - Stripe Subscriptions - API Integrations - MCP Connectors Learn more](https://app369.com/service/saas-development/) [

**Backend & API Development**

APIs, data models, background jobs and security rules in Node.js and TypeScript on Firebase and Google Cloud. - REST APIs - Firestore Data Models - Background Jobs & Queues - Security Rules & Cloud Cost Learn more](https://app369.com/service/backend-development/) [

**Payments & Integrations**

Stripe billing and checkout, Twilio texting and calls, email and calendar integrations, tested before real money moves. - Stripe Subscriptions & Checkout - Stripe Connect Payouts - Twilio SMS & Voice - Email & Calendar APIs Learn more](https://app369.com/service/payments-integrations/) [

**SEO, GEO & AEO**

Found and quoted by Google and by AI assistants: citation audits, structured data, answer pages and AI crawler rules, at fixed prices. - AI Citation Audits - Structured Data - Answer-Ready Pages - llms.txt & Crawler Rules Learn more](https://app369.com/service/seo-geo-aeo/) [

**UI/UX Design**

Research-driven design in Figma that delivers measurable results. - User Interface Design - User Experience Design - Wireframing & Prototyping - Design Systems Learn more](https://app369.com/service/ui-design/) [

**Technical Consulting**

Consultations help you choose the right stack and strategy before you invest. - Technology Stack Selection - Architecture Planning - Code Review & Audit - Digital Transformation Learn more](https://app369.com/service/consultations/) [

**Maintenance & Support**

App369's support plans include bug fixes, security patches, OS updates, and crash and uptime monitoring, with critical issues handled first. - Bug Fixes & Updates - Performance Optimization - Security Patches - Crash & Uptime Monitoring Learn more](https://app369.com/service/ongoing-maintenance/) ## **Prefer a fixed price?** Fixed scope, fixed price, paid upfront. The work happens in writing; no call needed. - [**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/) - [**AI-Built App Rescue**from $450A Lovable, Bolt or Cursor app checked end to end in 3 days, then its worst problems fixed at a fixed price.](https://app369.com/fixed-price/ai-app-rescue/) - [**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/) - [**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/) ## **Data and research** - [**Fixed-Price App Development Prices 2026**](https://app369.com/statistics/fixed-price-app-development-prices-2026/) What sellers publish for a bug fix, Stripe subscriptions, a rules audit, an AI-built app rescue and a web MVP. - [**App Development Statistics 2026**](https://app369.com/statistics/app-development-statistics-2026/) App Store and Google Play economics, store fees and review times, mobile OS share and framework usage, each sourced. Start here ## **Start with your project** Describe your project and receive a technical assessment by email, usually within one business day. Prefer to talk? Consultations are $100 per 15 minutes, paid upfront. [**Get a Free Quote **→](https://app369.com/contact/) [**View Pricing**](https://app369.com/fee-structure/) Fiverr reviews / 95 on app work ## **What buyers said about this kind of work** [**Read 126 of the 127 reviews **](https://app369.com/reviews/) - - - ### **Read the whole story** - [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, 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)