Hire the Best Backend Rest API Professionals

I help founders and product teams ship production backends and AI systems on cloud — APIs, serverless, RAG, and workflows on real data — not demos and not throwaway MVPs. Top Rated · $80k+ on Upwork · 27 reviews · 34 completed jobs. Clients consistently cite expert AWS/TypeScript/serverless delivery, excellent code quality, clear teaching and handoff, and long-term collaboration. WHAT I ENGINEER (AI Systems Engineering) • Production backends — NestJS/Node, Postgres/DynamoDB, event-driven APIs • Cloud-native systems — AWS Lambda, API Gateway, Cognito; GCP Cloud Run; Azure SSO patterns • AI in production — RAG/document Q&A, LangChain backends, MCP integrations, conversational AI with handoff, AI OS agents and workflows on real data • Auth & platforms — OAuth, JWT, Passkeys-class patterns; multi-tenant SaaS foundations PROOF — shipped systems • Fintech auth at scale — Passkeys & social login (Deriv, NestJS) • Enterprise expense ops — serverless employee/admin portals + Azure SSO (Forte Construction) • Marketplace backend — search, feeds, event-driven commerce (Circlin) • Medical staffing — serverless portals + ATS/Bullhorn integrations (Frontera Search Partners) • AI document & chat backends — LangChain, RAG, serverless deploy paths (V1 Digital, legal-tech) • GCP data pipeline modernization — Flask → Cloud Run + Scheduler; ~80% cost reduction on a major pipeline (Upwork client) • Document AI for construction quotes — OCR + LLM + rules on AWS (Textract-class patterns) WHAT CLIENTS SAY (from Upwork reviews) • "Expert in AWS, TypeScript and Serverless" — repeat collaborator, highly recommended (Ferhat K.) • "One of the best freelancers I have ever worked with" — rapid, cost-efficient cloud-native delivery; fantastic teacher (Neil B.) • Collaborating 1+ year; detail-oriented; not afraid of new challenges (Victor S.) • "Pillar of support" — depth of knowledge, thorough, covers all angles (Danny T.) • Excellent code quality and pointed architectural input (Pablo R.) • Knowledgeable AWS, clear English, hire again (Yuanbo G.) START FAST — PROJECT CATALOG Fixed packages for NestJS API starters, RAG/PDF Q&A, AWS deploy, WhatsApp FAQ bots, and landing pages — scoped deliverables in days, then expand to full systems. CUSTOM ENGAGEMENTS Platforms, marketplace backends, ops portals, and AI layers — milestone-based with source code and deploy notes. Stack: TypeScript · NestJS · AWS · GCP · PostgreSQL · DynamoDB · LangChain · OpenAI · Docker Dubai, UAE — own visa, fully authorized to work in UAE. Remote US/EU/MENA. Message with your system, stack, and timeline — or order a Catalog package to start.

I help founders and teams get unstuck when a Laravel, React, or Next.js SaaS product needs to move forward without breaking what already works, whether that's stabilizing an existing Laravel SaaS, building a Marketplace with React and Next.js, adding an AI Chatbot layer to a SaaS platform built on Laravel that already has users, or picking up a Next.js, React, or Laravel SaaS Marketplace codebase someone else left behind. Top Rated on Upwork, 100% Job Success, $30k+ earned. Where I fit best: ✔ Laravel backend development, API integration, and database design ✔ Stabilizing, auditing, and extending existing Laravel, React, and Next.js SaaS platforms ✔ Two-sided Marketplace builds with React, Next.js, and Laravel: listings, lead management, and payment gateway integration ✔ AI Chatbot and OpenAI API integration inside existing Next.js, React, and Laravel SaaS products ✔ React dashboards, Next.js admin panels, and Laravel-powered internal tools ✔ React and Next.js performance optimization, from code splitting to SSR/SSG tuning ✔ Bug fixing, performance work, and ongoing maintenance across Laravel, Next.js, and React SaaS codebases ✔ Full-stack builds combining Laravel, React, and Next.js when the project needs both ends done right, from Marketplace platforms to AI Chatbot features I'm comfortable working alongside AI-assisted workflows like Claude Code and Cursor to move faster on Laravel, React, and Next.js SaaS and Marketplace projects, but I still read and understand every line of Laravel, React, and Next.js code before it ships. What clients say: "Kezia produces very high quality work and is committed to successful outcomes.", client review, Laravel SaaS code review project "Kezia is genuinely impressive... on time, reliable, very proactive, and goes above and beyond the brief.", client review, ongoing React, Next.js, and AI Chatbot integration project I ask questions to clarify tasks and scope, and I give daily progress updates so you're never wondering where things stand. If something outside scope needs fixing, I flag it and ask before touching it, not after. If you have a Laravel, React, or Next.js SaaS project that needs a steady hand, an existing platform to stabilize, a Marketplace build, or an AI Chatbot feature done properly, send me the details and I'll tell you honestly how I'd approach it. Whether the work leans React on the frontend, Next.js for the framework layer, or centers on a Marketplace and AI Chatbot build from scratch, I bring the same care to every Marketplace and AI Chatbot project I take on, with AI Chatbot integration handled end to end.

I am an experienced Python Developer with 5+ years of experience delivering high-performance backend architectures, SaaS solutions, intelligent automation systems, and AI-driven applications using Django, FastAPI, and industry-leading Python technologies. Core Expertise & Technology Stack ============================= 𝗔𝗜 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴, 𝗟𝗟𝗠𝘀 & 𝗚𝗲𝗻𝗲𝗿𝗮𝘁𝗶𝘃𝗲 𝗔𝗜 Extensive experience building AI-powered applications using OpenAI (GPT-4/4o), Claude, Gemini, Llama, DeepSeek, Qwen, Mistral, and Hugging Face. Skilled in fine-tuning, embeddings, vector search, model orchestration, MCP, function calling, and custom AI workflows. 𝘼𝙄 𝘼𝙜𝙚𝙣𝙩𝙨 & 𝘼𝙪𝙩𝙤𝙣𝙤𝙢𝙤𝙪𝙨 𝙎𝙮𝙨𝙩𝙚𝙢𝙨 Design and development of intelligent agent ecosystems using LangGraph, LangChain, CrewAI, AutoGen, OpenAI Agents SDK, Hermes, Mastra, and PydanticAI. Expertise in multi-agent architectures, tool integration, agentic workflows, AI copilots, and autonomous decision-making systems. 𝘼𝙄 𝙋𝙧𝙤𝙙𝙪𝙘𝙩𝙨 & 𝙎𝙖𝙖𝙎 𝘿𝙚𝙫𝙚𝙡𝙤𝙥𝙢𝙚𝙣𝙩 Building production-ready AI applications with Vercel AI SDK, Next.js, streaming AI interfaces, conversational assistants, and scalable AI SaaS platforms. 𝗥𝗔𝗚, 𝗦𝗲𝗮𝗿𝗰𝗵 & 𝗞𝗻𝗼𝘄𝗹𝗲𝗱𝗴𝗲 𝗠𝗮𝗻𝗮𝗴𝗲𝗺𝗲𝗻𝘁 Implementation of Retrieval-Augmented Generation (RAG) systems using LlamaIndex, Haystack, Pinecone, Weaviate, Qdrant, ChromaDB, and FAISS. Experienced in semantic search, hybrid retrieval, knowledge graphs, and enterprise knowledge systems. 𝗩𝗼𝗶𝗰𝗲 𝗔𝗜 & 𝗖𝗼𝗻𝘃𝗲𝗿𝘀𝗮𝘁𝗶𝗼𝗻𝗮𝗹 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗶𝗼𝗻 Development of real-time voice applications using LiveKit, Vapi, Retell AI, Bland AI, ElevenLabs, and Whisper. Expertise in AI voice agents, speech recognition, text-to-speech, IVR automation, and conversational workflows. 𝗕𝗿𝗼𝘄𝘀𝗲𝗿 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗶𝗼𝗻 & 𝗔𝗜 𝗔𝗴𝗲𝗻𝘁𝘀 Creating autonomous browser agents and computer-use systems with Browser Use, Stagehand, web automation frameworks, and intelligent workflow orchestration. 𝘼𝙄 𝙈𝙤𝙣𝙞𝙩𝙤𝙧𝙞𝙣𝙜 & 𝙊𝙥𝙩𝙞𝙢𝙞𝙯𝙖𝙩𝙞𝙤𝙣 Experience with LangSmith, LangFuse, Arize Phoenix, prompt evaluation, LLM observability, AI analytics, and performance monitoring for production AI systems. 𝐀𝐮𝐭𝐨𝐦𝐚𝐭𝐢𝐨𝐧 & 𝐓𝐡𝐢𝐫𝐝-𝐏𝐚𝐫𝐭𝐲 𝐈𝐧𝐭𝐞𝐠𝐫𝐚𝐭𝐢𝐨𝐧𝐬 Building automated business workflows using n8n, Zapier, Make, REST APIs, Webhooks, Twilio, WhatsApp API, HubSpot, Salesforce, and custom CRM/ERP integrations. 𝐁𝐚𝐜𝐤𝐞𝐧𝐝 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐢𝐧𝐠 & 𝐂𝐥𝐨𝐮𝐝 𝐈𝐧𝐟𝐫𝐚𝐬𝐭𝐫𝐮𝐜𝐭𝐮𝐫𝐞 Strong background in Python, FastAPI, Django, Node.js, Docker, AWS, GCP, Azure, LiteLLM, Ollama, vLLM, microservices, scalable APIs, and serverless architectures. 𝙁𝙧𝙤𝙣𝙩𝙚𝙣𝙙 𝘿𝙚𝙫𝙚𝙡𝙤𝙥𝙢𝙚𝙣𝙩 Modern web application development using React, Next.js, TypeScript, and Vercel, Shopify and Shopify App development and user-friendly interfaces. 𝗗𝗮𝘁𝗮𝗯𝗮𝘀𝗲𝘀 & 𝗗𝗮𝘁𝗮 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴 Proficient with PostgreSQL, MongoDB, Redis, Supabase, ETL pipelines, real-time data processing, analytics systems, and large-scale data architectures. So if you are looking for someone who can build a solid backend and connect it perfectly with a modern frontend then I would love to help bring your idea to life.

Hi, I’m Sandeep — A full stack software engineer with 5+ years of hands-on experience building modern, fast, and secure web applications using PHP I work like a professional product team: ✔️ I Have pain subscription of cursor ai and know how to use efficiently to create/debug. ✔️ Use GitHub or Bitbucket for clean version control ✔️ Write clean, maintainable, production-ready code ✔️ Integrate APIs with strong client-side validation and error handling ✔️ Deliver complete documentation — from API usage to deployment steps ✔️ Optimize websites for speed, SEO, and responsiveness ✅ What I Can Do for You: Custom Dashboards & Admin Panels Booking Systems, Multi-Page Applications, SaaS Applications, Market Place applications REST API Development SEO Optimization, Lighthouse Improvements Full project setup with codebase + documentation + deployment Lando, Docker 📄 Deliverables I Include: Clean and well-structured source code GitHub or Bitbucket API integration guide or documentation Deployment-ready files and instructions (S3, GCP, Hostinger, VPS, etc.) Optional post-delivery support Clients hire me because I’m fast, reliable, and communicative — and I take full ownership of the project. If you're looking for a developer who will think beyond code and deliver business-ready solutions, let’s connect. Let me know if you want a version customized further for e-commerce, SaaS, or admin dashboards, or a separate bio section for your specialized project catalog.

My name is Derartu, a full stack software engineer based in Addis Ababa, Ethiopia. Over the past few years, I've built backend systems, RESTful APIs, and cross platform applications using Django, NestJS, and Node.js, with real world experience in API gateway design, Redis caching, and third-party payment integrations. I also build modern frontends with React and Next.js, and mobile apps with Flutter and Kotlin. My focus is delivering complete, working products end to end without sacrificing the backend reliability and system design clients need as they grow. On the backend side, I specialize in building robust, scalable APIs using Django REST Framework, NestJS, and Node.js. I have real world experience designing API gateways, implementing caching strategies with Redis, and applying rate limiting to keep systems performant under load. I've also integrated third-party payment systems, including Telebirr, working directly with both SOAP and REST APIs a service that's often overlooked but critical for any platform handling real transactions. Whether you need a new backend built from scratch or an existing one optimized for reliability, I can help. Beyond the backend, I build modern, responsive frontends with React and Next.js, and cross-platform mobile apps with Flutter and Kotlin. This means I can take a project from idea to fully working product without you needing to coordinate between multiple freelancers one point of contact, consistent code quality, and faster delivery. I've built full platforms end to end, including a microservice based job matching platform, an Instagram style social app (web + mobile), a role based idea submission platform, a plug and play blog system, and a book e commerce platform integrated with the Google Books API. I containerize services with Docker, follow foundational DevOps practices to keep deployments smooth, and apply core application security practices across every API I build. I've worked across a range of project types social platforms, marketplaces, internal tools, and e commerce which means I can adapt quickly to new domains instead of needing everything explained from scratch. Here's a quick breakdown of what I offer: Backend & API Development — Django, NestJS, Node.js Frontend Development — React, Next.js Mobile App Development — Flutter, Kotlin, React Native System Design — API gateways, Redis caching, rate limiting Third-Party & Payment Integration — SOAP, REST, Telebirr Docker containerization & deployment support

Why hire me? I work with teams moving fast on AI — shipping features, MVPs, and products faster than most — and make sure what gets built holds up past the demo: backend systems that can't afford to fail (HIPAA-conscious healthcare platforms, payment flows that have to reconcile perfectly), and AI/RAG pipelines that survive real traffic, not just a screen-share. Most freelancers can describe this work. I've shipped it — live, in production, for clients who couldn't afford it to go wrong. What makes me different → I don't bolt on an API call and call it "AI integration." I design retrieval, structure outputs, and handle the failure modes that only show up under real traffic. → I've built this inside systems where mistakes were expensive: multi-tenant SaaS, payment processing, HIPAA-conscious healthcare infrastructure. → I own the system, not just the ticket — I find where things break and fix them cleanly, not just where I'm told to look. Track record 🏆 Top Rated Freelancer 💰 $140K+ earned on Upwork ⏱️ 5,400+ hours delivered 🚀 42 successful production deployments What I'm best at ⚡ AI-speed builds, made production-ready Reviewing, hardening, and scaling apps built fast with AI tooling — so the backend doesn't buckle the moment real users show up. 💠 RAG & LLM systems Retrieval pipelines, structured LLM outputs, and AI workflows built to survive production traffic — not prompt wrappers stitched onto an API. 💠 Backend for regulated & high-stakes SaaS Django, FastAPI, PostgreSQL — multi-tenant architecture, audit-minded design, RBAC, private AWS VPC networking. 💠 Payments & integrations Processor flows, webhooks, reconciliation, and reporting across account types — the parts of the system that can't be allowed to silently fail. 💠 Cloud delivery AWS, Docker, CI/CD — deployed, monitored, and maintained, not just spun up once and handed off. Proof ▪ Multi-tenant locker SaaS — FastAPI + React, real-time device signaling across mobile/kiosk clients, integrated payment processing ▪ AI threat-intelligence platform — retrieval-driven analysis with structured, automated reporting in place of manual review ▪ HIPAA-conscious healthcare platform — private AWS VPC, RBAC, audit-minded design for regulated referral data If you're moving fast with AI and need the backend to hold up under real usage — or a system built by someone who's already broken these in the ways that matter — message me with the stack and the problem.