Hire the Best B4X Developers

More than 3,000 reviews on G2
Rating is 4.5 out of 5.
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Gopal H.

Surat, India

$18/hr
4.9
63 jobs

๐Ÿš€ Top Rated Plus | 9+ Years Experience | 8100+ Hours | 100% Job Success Hi, I'm Gopal, a Senior Full-Stack Web Developer & AI Application Specialist with over 9 years of experience delivering secure, scalable, and high-performance applications. I specialize in end-to-end development, from clean and responsive user interfaces to powerful backend systems. I also built and productionised AI platforms similar to Lovable, ChatGPT, and Base44, including private deployments, API integrations, and automation workflows. Whether you need a SaaS platform, an AI chatbot, a business automation system, an eCommerce solution, or a Base44 app rebuilt outside the platform, I deliver solutions that are reliable, maintainable, and built to scale. ๐Ÿง  AI & Automation โœ… Lovable-style AI apps โœ… ChatGPT-like conversational systems โœ… Base44 app duplication & migration โœ… AI agents & workflow automation โœ… API-driven AI integrations ๐Ÿงฑ Backend & Frameworks โœ… Laravel / Filament โœ… CodeIgniter โœ… WordPress (Custom Themes & Plugins) โœ… CakePHP ๐ŸŽจ Frontend & Realtime โœ… ReactJS โœ… VueJS โœ… JavaScript (ES6+) โœ… jQuery / AJAX โœ… WebSockets ๐Ÿ—„๏ธ Databases & APIs โœ… REST API development & integration โœ… MySQL โœ… MongoDB ๐ŸŒ Web & Design โœ… HTML / HTML5 โœ… CSS / Bootstrap โœ… Social media integrations โœ… Photoshop I communicate clearly in spoken and written English and am known for being proactive, reliable, and deadline-driven. Client satisfaction comes from clean code, transparency, and consistent delivery.

  • MySQL
  • Laravel
  • CodeIgniter
  • CakePHP
  • React
  • API Integration
  • Payment Gateway Integration
  • Vue.js
  • Ecommerce Website Development
  • React Native
  • REST API
  • AI Chatbot
  • AI Product Management
  • n8n
  • Make.com
  • HighLevel
Haider Z.

Islamabad, Pakistan

$30/hr
5.0
8 jobs

I'm an AI developer who builds production AI systems, not demos. AI agents, RAG pipelines, LLM integrations, and automation workflows that handle real traffic and solve real business problems. Top Rated | 100% Job Success | 100% Client Recommendation. What I build as an AI developer: AI Agents and Agentic Workflows: Multi-agent systems with LangChain, LangGraph, and CrewAI. Tool-calling agents, function execution, MCP integrations, and autonomous workflows that run reliably in production. RAG Pipelines: Retrieval-augmented generation systems with vector databases (Pinecone, ChromaDB, pgvector). Document intelligence, knowledge base Q&A, and semantic search that returns accurate results instead of hallucinations. LLM Integration: Production integrations with OpenAI, Claude, and Gemini APIs. Streaming responses, tool-use workflows, structured outputs, and multi-model architectures. I've built AI features inside SaaS platforms, mobile apps, and real-time data pipelines. AI Chatbots and Assistants: Context-aware support bots, sales agents, and internal tools connected to your CRM, Slack, knowledge base, or calendar. Web, WhatsApp, and API deployments. AI Automation: Workflow automation that replaces manual processes. Lead qualification, data extraction, content generation, and business process automation with Python and FastAPI backends. What sets me apart from most AI developers: I come from a production backend engineering background. Before going deep into AI development, I built high-throughput systems: a programmatic ad-tech platform processing millions of requests in Go, real-time data pipelines with Kafka and ClickHouse, scoring and fraud detection algorithms, and scalable SaaS applications with Node.js and Python. That means the AI systems I build don't break under load. Stack: Python (FastAPI, LangChain, LangGraph, CrewAI), Node.js/TypeScript (NestJS), Go. OpenAI, Claude, Gemini APIs. Pinecone, ChromaDB, pgvector. PostgreSQL, MongoDB, Redis. Kafka, Docker, AWS. Ideal AI projects for me: Custom AI agent development (LangChain, LangGraph, CrewAI) RAG systems and document intelligence pipelines LLM integration into existing SaaS or internal tools AI chatbots and conversational AI assistants AI-powered automation and workflow orchestration Backend infrastructure for AI-native applications I respond within a few hours, ship documented code with full repo access, and build AI systems that keep working after the contract ends. Need an AI developer who can ship production systems? Send a message or invite me to your job.

  • AI Agent Development
  • LangChain
  • Python
  • Artificial Intelligence
  • Prompt Engineering
  • AI Chatbot
  • Retrieval Augmented Generation
  • OpenAI API
  • Natural Language Processing
  • FastAPI
  • Large Language Model
  • Automation
  • Node.js
  • NestJS
  • API Development
  • Golang
  • PostgreSQL
  • Docker
  • Amazon Web Services
  • Back-End Development
Saman F.

Islamabad, Pakistan

$45/hr
5.0
10 jobs

I usually get involved when a business has one or more complex problems to solve. It might be a B2B or B2C platform that needs APIs, integrations, payments, or storefront work. I have spent around 350 hours developing and maintaining APIs for Fastkey and 200 hours managing a Replit project, its integrations, and ongoing development. However, this only reflects my work completed through Upwork. Outside Upwork, I have spent over half a decade working with Amazon, Shopify, Temu, WooCommerce, BigCommerce, custom storefronts, and eCommerce systems. I am comfortable building from scratch, fixing bugs, and continuing to scale live systems. Other builds include: โœ… Magento development and troubleshooting โœ… eCommerce systems covering catalogs, orders, payments, inventory, and fulfillment โœ… Connecting third-party platforms and APIs to retrieve and synchronize data โœ… Android kiosk solutions with remote management and device controls โœ… Paywall and payment integrations using RevenueCat, Stripe, and PayPal โœ… Setting up WordPress across multiple domains I keep the work straightforward. First, I understand how the business and current system operate. Then I make the technical changes without adding unnecessary complexity. If your project needs someone who can work across the complete system rather than only one framework, feel free to get in touch.

  • SaaS Development
  • Ecommerce Store Setup
  • WordPress
  • Shopify
  • Amazon
  • Third-Party Integration
  • Replit
  • Acumatica
  • Kiosk
  • Oracle NetSuite
  • Payment Gateway Integration
  • Stripe
  • PayPal
  • Data Center Migration
  • Domain Migration
  • Next.js
  • TikTok Ad
  • Ad Setup
  • Web Page
  • Claude
Zlatko M.

Zivinice, Bosnia and Herzegovina

$65/hr
5.0
19 jobs

โšก 100% Job Success ๐Ÿ”ฅ 80+ five-star reviews across platforms* ๐Ÿš€ 120+ shipped ๐Ÿ’ผ 7+ years ๐ŸŒ US & EU founders. I take over AI-built codebases and fix what actually matters. Your app was built fast with Lovable, Cursor, Claude Code, Bolt, Replit, or v0, and now the real problems are starting to show. Maybe auth is breaking, Supabase permissions are wrong, Stripe is failing in production, or deployments keep falling over. That is usually where I come in. I do not automatically rewrite the whole thing. I figure out what is actually causing the problems, fix the parts that matter, get the product stable, ship the next version, and stay on if you need someone to keep building it. โžก๏ธ Clients love when I fix these in 48 hours: โ€ข Supabase auth inconsistent โ€ข RLS exposing data or blocking wrong users โ€ข Stripe test works, production doesn't โ€ข Subscriptions, billing portal, or webhooks unreliable โ€ข Vercel deploys suddenly failing โ€ข Env vars and API keys a mess โ€ข APIs fail silently โ€ข Onboarding half-finished โ€ข Works on desktop, broken on mobile โ€ข AI code duplicated and nobody wants to touch it โ€ข Outgrew Lovable/Cursor but keeping the product โ€ข MVP exists and you need one engineer to own the codebase โžก๏ธ Stack: Frontend: Next.js, React, TypeScript, dashboards, onboarding, admin panels Backend: Supabase, PostgreSQL, Firebase, auth, RLS, roles, Edge Functions Payments: Stripe checkout, subscriptions, webhooks, live-mode bugs AI: OpenAI, Claude, Gemini, n8n, third-party APIs Infra: Vercel, GitHub, deployment debugging โžก๏ธ Best fit: you already have something. Users maybe. Codebase maybe messy. You need one person to read it, fix what matters, and keep shipping. Not a rebuild from scratch. โžก๏ธ Good fit: You like to move fast and don't like to deal with BS. โžก๏ธ Recent work: StrikeOS: AI coaching, video analysis, scoring workflows EditLayer: real-time editing layer for Next.js sites Trend Finder: AI trend product, multiple data sources Preflight: automated website QA with AI remediation โžก๏ธ How the workflow usually works: 1. You send the product or repo, what works, what's broken, what needs to ship next, and your deadline 2. I tell you quickly if I am a strong fit and what I would tackle first 3. We fix the highest-risk issues first: auth, payments, data access, deployments 4. I ship the next version and stay on if you want ongoing help โžก๏ธ Send me a message with your repo or product link. I will reply fast with whether I can help and where I would start. โžก๏ธ Relevant expertise: Next.js Developer, Supabase Developer, AI App Developer, SaaS Developer, Full-Stack Developer, Lovable Developer, Cursor Developer, Claude Code Developer, Stripe Integration, Supabase Auth, Supabase RLS, SaaS MVP, AI SaaS, API Integration, MVP to Production, Production Engineering, Vercel Deployment, PostgreSQL, React, TypeScript, Bolt Developer, Replit Developer, v0 Developer, Webhook Integration, Authentication, Row Level Security, Next.js App Router, SaaS Production, Fractional Engineer, Product Engineer *Reviews across Upwork and direct client work.

  • Next.js
  • React
  • TypeScript
  • Supabase
  • Stripe
  • SaaS Development
  • AI App Development
  • Full-Stack Development
  • PostgreSQL
  • JavaScript
  • OpenAI API
  • API Integration
  • Firebase
  • Front-End Development
  • Back-End Development
  • Artificial Intelligence
  • Claude
  • n8n
  • Vercel
  • Web Application
Raj M.

Ahmedabad, India

$20/hr
4.8
33 jobs

I build AI agents, Voice AI, and business automation systems that connect conversations, business data, and real actions. If you need an AI receptionist, WhatsApp assistant, lead qualification workflow, RAG-powered application, or AI feature inside an existing product, I can help you design and build it. My work focuses on: AI Agents & AI Assistantsโ€” Custom agents that understand requests, use tools, and complete business tasks. Voice AI & AI Receptionistsโ€” Voice agents for inbound calls, customer support, lead qualification, and real-time actions. WhatsApp AI & Automation โ€” AI-powered conversations, lead capture, follow-ups, and CRM workflows. RAG & Knowledge-Based AIโ€” Systems that retrieve information from business documents, databases, and knowledge bases. CRM & API Integrationsโ€” Connecting AI with CRMs, calendars, third-party APIs, and existing applications. AI-Powered SaaS โ€” Full-stack AI products with frontend, backend, authentication, databases, and deployment. A typical workflow might look like: Lead โ†’ AI Qualification โ†’ CRM โ†’ Follow-up โ†’ Appointment โ†’ Human Handoff I handle the complete development process, from AI architecture and agent logic to backend development, integrations, automation, testing, and deployment. Tech I work with: OpenAI, Claude, Gemini, RAG, n8n, React, Next.js, Node.js, Python, FastAPI, PostgreSQL, MongoDB, Redis, APIs, and Docker. I focus on practical, production-oriented AI systems that solve real business problemsโ€”not just basic chatbots or disconnected prototypes. If you have an AI idea, an existing application, or a workflow you want to automate, send me the details. I can help you turn it into a working solution.

  • AI Agent Development
  • AI Development
  • AI Chatbot
  • Voice & Tone Consistency
  • OpenAI API
  • n8n
  • API Integration
  • HighLevel
  • CRM Software
  • Conversational AI
  • Twilio
  • WhatsApp
  • Appointment Scheduling
  • Retrieval Augmented Generation
  • Python
  • Node.js
  • React
  • Next.js
  • TypeScript
  • Claude
Noman R.

Karachi, Pakistan

$5/hr
4.5
166 jobs

๐‡๐ž๐ซ๐ž'๐ฌ ๐ญ๐ก๐ž ๐๐ž๐š๐ฅ: Share your idea, and weโ€™ll turn it into a functional, scalable, and beautifully designed app that solves real problems and generates revenue. ๐—›๐—ผ๐˜„ ๐—ฌ๐—ผ๐˜‚๐—ฟ ๐—ฃ๐—ฟ๐—ผ๐—ท๐—ฒ๐—ฐ๐˜ ๐— ๐—ผ๐˜ƒ๐—ฒ๐˜€ ๐—™๐—ฟ๐—ผ๐—บ ๐—œ๐—ฑ๐—ฒ๐—ฎ ๐˜๐—ผ ๐—Ÿ๐—ถ๐˜ƒ๐—ฒ ๐—ฃ๐—ฟ๐—ผ๐—ฑ๐˜‚๐—ฐ๐˜: Every project follows a clear, proven journey, divided into milestones: UI/UX design โ†’ Front-end development โ†’ Backend development โ†’ Deployment โ†’ Post-launch maintenance (8 weeks FREE) This ensures transparency, predictable delivery, and zero surprises. ---------------------------------------------- I offer a ๐—ณ๐—ฟ๐—ฒ๐—ฒ ๐Ÿฏ๐Ÿฌ-๐—บ๐—ถ๐—ป๐˜‚๐˜๐—ฒ ๐—ฐ๐—ผ๐—ป๐˜€๐˜‚๐—น๐˜๐—ฎ๐˜๐—ถ๐—ผ๐—ป to discuss and refine your idea, recommend the right tech stack, and forecast any ongoing costs as your user base grows, so you avoid surprises and make informed decision with clarity. ---------------------------------------------- Words from a recent client after working with us: (check more on my profile below) "Noman Razzaq ๐™ž๐™จ ๐™ซ๐™š๐™ง๐™ฎ ๐™ฅ๐™ง๐™ค๐™›๐™š๐™จ๐™จ๐™ž๐™ค๐™ฃ๐™–๐™ก ๐™–๐™ฃ๐™™ ๐™ž๐™จ ๐™–๐™ก๐™ฌ๐™–๐™ฎ๐™จ 10 ๐™จ๐™ฉ๐™š๐™ฅ๐™จ ๐™–๐™๐™š๐™–๐™™ ๐™ค๐™› ๐™ ๐™ฃ๐™ค๐™ฌ๐™ž๐™ฃ๐™œ ๐™ฌ๐™๐™–๐™ฉ ๐™ฉ๐™๐™š ๐™—๐™ช๐™ž๐™ก๐™™ ๐™ฃ๐™š๐™š๐™™๐™จ. ๐™’๐™š ๐™–๐™ง๐™š ๐™˜๐™ค๐™ฃ๐™ฉ๐™ž๐™ฃ๐™ช๐™ž๐™ฃ๐™œ ๐™ฉ๐™ค ๐™ฌ๐™ค๐™ง๐™  ๐™ฉ๐™ค๐™œ๐™š๐™ฉ๐™๐™š๐™ง ๐™–๐™ฃ๐™™ ๐™„ ๐™๐™–๐™ซ๐™š ๐™–๐™ก๐™ง๐™š๐™–๐™™๐™ฎ ๐™ง๐™š๐™˜๐™ค๐™ข๐™ข๐™š๐™ฃ๐™™๐™š๐™™ ๐™๐™ž๐™ข ๐™ฉ๐™ค ๐™ค๐™ฉ๐™๐™š๐™ง ๐™˜๐™ค๐™ข๐™ฅ๐™–๐™ฃ๐™ž๐™š๐™จ." โญโญโญโญโญ - ๐˜ผ๐™ก๐™ž๐™˜๐™ž๐™– ๐˜พ๐™ค๐™ฌ๐™–๐™ฃ ๐™๐™ค๐™ช๐™ฃ๐™™๐™š๐™ง ๐™ˆ๐™š๐™จ๐™ข๐™š๐™ง (๐™๐™ฃ๐™ž๐™ฉ๐™š๐™™ ๐™†๐™ž๐™ฃ๐™œ๐™™๐™ค๐™ข) ---------------------------------------------- I've majored in software engineering, and I've used a myriad of technologies to help various businesses create mobile apps that have generated millions in revenue. Over the past 5+ years, I have developed a wide range of iOS and Android mobile apps. โœ… Food delivery app โœ… Ride booking app (like Uber) โœ… Real estate listing app (Like Airbnb) โœ… Social media mobile app (like TikTok/Instagram) โœ… Startups/Investment management mobile app โœ… Wellness mobile app โœ… Fitness and Nutrition mobile app (like CalAI, MyFitnessPal) โœ… Sports mobile app โœ… E-commerce mobile app โœ… Language Learning Mobile App (Like Duolingo) โœ… Event management mobile app โœ… Grocery/Meal Planning mobile app โœ… Freelance mobile app โœ… Service Booking Mobile App (Home/HVAC) โœ… Inventory Management Mobile App โœ… Learning Management Mobile App โœ… Appointment Booking Mobile App (Salon/Doctor) โœ… Venue Booking Mobile App (Sports/Events) โœ… Task Management Mobile App (Project Management/To-Do) โœ… On-Demand Custom Mobile Apps ---------------------------------------------- As your ๐˜๐—ฒ๐—ฐ๐—ต๐—ป๐—ถ๐—ฐ๐—ฎ๐—น ๐—ฝ๐—ฎ๐—ฟ๐˜๐—ป๐—ฒ๐—ฟ, I go above and beyond to ensure your appโ€™s success, from concept to launch. What I Also Bring Beyond Development: โ†’ Technology & architecture consulting โ†’ Product roadmap & feature prioritization โ†’ Help you understand any possible ongoing costs with the project โ†’ Cost-effective tech stack selection with long-term cost planning โ†’ Scalability strategy as your user base grows โ†’ Technical support during investor or stakeholder discussions ---------------------------------------------- ๐— ๐—ฎ๐—ถ๐—ป๐˜๐—ฒ๐—ป๐—ฎ๐—ป๐—ฐ๐—ฒ & ๐—Ÿ๐—ผ๐—ป๐—ด-๐—ง๐—ฒ๐—ฟ๐—บ ๐—ฆ๐˜‚๐—ฝ๐—ฝ๐—ผ๐—ฟ๐˜ I provide free post-delivery support for 8 weeks, followed by flexible maintenance plans based on your product needs, usage scale, and future roadmap, always discussed transparently. ---------------------------------------------- ๐Ÿš€ If youโ€™re looking for someone who understands your product, owns outcomes, communicates clearly, and thinks long-term, letโ€™s connect and build something solid. โ—โ— Check out my portfolio! โ—โ— Highlighted Skills: Full Stack Developer | Expert Full Stack Developer | Full Stack Mobile App Developer | Full Stack AI Developer | Expert Full Stack Mobile App Developer | Mobile Developer | iOS Developer | Android App Developer | Mobile App Development | Cross platform development | AI App Developer | AI App | Mobile Developer | App Developer | Mobile App Development Consultation | IT Consultation | App Developer | AI App Developer | iOS App Development | iOS App | Android App Development | Hybrid App development | Mobile App Development Consultation | Flutter | Firebase | Dart | Flutter Dart | Flutter Firebase | iOS Development | Android App Development | Smartphone | User Authentication | In App Purchases | API Integration

  • Mobile App Redesign
  • Android App Development
  • App Development
  • Mobile App Development
  • Mobile App Design
  • Mobile App
  • iOS Development
  • Smartphone
  • AI App Development
  • Hybrid App Development
  • Flutter
  • Firebase
  • AI Mobile App Development
  • React Native
  • Website to Mobile App Conversion
  • Android App
  • iOS
  • Figma
  • UX & UI Design
  • Mobile App Development Consultation

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