Hire the Best JSON Developers

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Rating is 4.8 out of 5.
4.8/5
Based on 1,960 client reviews
Alex C.

Boryspil, Ukraine

$29/hr
5.0
19 jobs

Experienced AI & Low-Code developer. I build production automation systems and mobile apps that actually ship — not prototypes. Two focus areas: AI automation (n8n): I design workflows that connect LLMs (OpenAI, Claude, Gemini) to real business processes — content generation pipelines, lead qualification and routing, document/image analysis, and multi-platform publishing. I build with structured JSON outputs, error handling, and retry logic by default, and I bake human review gates into the parts that matter (compliance, brand approval, anything that shouldn't auto-publish on a hallucination) rather than chasing full automation for its own sake. FlutterFlow app development: production iOS/Android apps with Firebase backend, RevenueCat subscriptions, and third-party API integrations — taken from spec through App Store/Play Store launch, not just prototyped. Selected experience: - Built and launched multiple production FlutterFlow apps on the App Store and Google Play, including one with OpenAI-powered personalization features - Designed n8n pipelines combining LLM-based classification/extraction, structured data storage (Airtable/Postgres/Supabase), and automated multi-step workflows for content, recruitment, and outreach use cases - Participated in building one of the biggest Adalo apps — MyLabourBase - Contributed to the fast-growing startup TimeLeft Tech stack: n8n, OpenAI / Claude / Gemini, FlutterFlow, Firebase, Supabase, Airtable, PostgreSQL, RevenueCat, Docker, Xano, Make, Google Cloud, AWS. I'm direct about scope and honest about what a system can and can't reliably do — you'll get a realistic estimate, not an oversold one. Let's talk about what you're trying to build.

  • Low Code & RAD Software
  • FlutterFlow
  • Adalo
  • JavaScript
  • iOS
  • Android
  • Google Cloud Platform
  • n8n
  • ChatGPT API
  • Gemini
Haris A.

Karachi, Pakistan

$44/hr
5.0
54 jobs

Most projects I'm hired for now start the same way: something already exists, it demos beautifully, and it won't survive a real user. Six years on Upwork, 50+ contracts, 100% JSS. I use AI tooling daily — it's genuinely fast at producing something that runs. What it doesn't produce is a system. It'll happily put an API key in the frontend, skip the empty state, ignore the error case, invent an auth check that runs client-side only, and duplicate the same logic across nine files. None of that shows up in the demo. All of it shows up in week one of real traffic. So a lot of my work now is picking up prototypes and making them into products. Not rewriting from scratch — that's usually wasteful, and the prototype already proved the idea. The job is finding the handful of decisions that will break under load and fixing those, then building properly on top of what's worth keeping. I do greenfield builds too. But if you've got something half-finished, inherited from another developer, or generated fast and now stuck, that's the situation I'm most useful in. What I actually do first I read the code and the real data before I quote. Not the docs — the actual API responses, the actual database, the actual repo. Documentation describes intent; the data tells you what's true, and the gap between them is where timelines vanish. Then you get a straight assessment: what's fine, what's fragile, what's dangerous, and what any of it costs. Sometimes the answer is that less needs fixing than you feared. I'd rather tell you that in the first conversation than bill for it. What I build React, TypeScript, Next.js on the front. Node and Python behind it. Dashboards, client portals, marketplaces, booking systems, internal tools. Heavy on integration — connecting a frontend to an API that already exists, third-party services, systems never designed to talk to each other. Auth and role-based access done server-side, where it can't be bypassed. AI features where they earn their place. I'm also a data engineer, Microsoft Fabric certified (DP-600, DP-700), building pipelines and Power BI reporting on Azure and AWS. That's why my applications hold up under real data: most developers guess at what arrives downstream. I've been the one generating it. How I work Working URL early, stays working. Progress is something you check, not something I report. Scope changes raised the week I spot them, not at handover. Written for whoever maintains it after me, assuming it won't be me. Your repo, your server, docs covering build, deploy, and rollback. Track record "The best freelance developer I have EVER worked with." · "Built the MVP I was looking for in record time." Send me the repo or a real API response, and I'll tell you what you're dealing with before either of us commits.

  • JSON
  • JavaScript
  • TypeScript
  • React
  • Next.js
  • API Integration
  • SQL
  • Python
  • Data Analysis
  • Microsoft Power BI
  • ETL Pipeline
  • Supabase
  • AI Development
  • AI Chatbot
  • Claude
  • Vercel
  • GitHub
  • API
  • Serverless Stack
  • Replit
Amar F.

Constantine, Algeria

$40/hr
4.9
86 jobs

Full-Stack Developer & AI Integration Specialist | 10+ Years | Tech Lead For the past 2+ years I served as Tech Lead at Amelkis Solutions, a financial software company building enterprise-grade EPM (Enterprise Performance Management) and financial consolidation platforms used by real clients across Europe. I owned the architecture, led feature development, and shipped production code across a .NET + React + SQL Server stack handling everything from OData API design to authentication systems (OAuth, OIDC, Clerk) to AI-powered chatbot integration. That experience gave me something most developers don't have: deep knowledge of what it takes to build software that handles real financial data, real compliance requirements, and real users who can't afford for it to break. WHAT I BUILD Full-Stack Web Applications React, Next.js, TypeScript, Node.js, Vue.js on the front end. .NET (C#), PHP/Laravel, Node.js on the back end. I've built SaaS platforms, enterprise dashboards, e-commerce solutions, tutoring platforms with live video (TeamLilit), and financial consolidation tools. AI & LLM Integration I build AI-powered features into real products not demos. At Amelkis I integrated a conversational chatbot into the EPM platform: LLM-powered intent detection, OData API data retrieval, structured output generation, fallback logic, and dual-mode routing (inline data display vs. app redirect based on payload size). I use Claude Code daily as a core development workflow, not a gimmick. WordPress & CMS Development Clean, fast, client-manageable WordPress sites across industries: industrial B2B, SaaS, and NDIS healthcare. I adapt to any brand tone and move fast theme, design, and build are not a bottleneck. API & Systems Integration OData, REST, third-party APIs (Meta Ads, Shopify, Klaviyo, Notion, payment processors, auth providers). I've built and consumed APIs at scale and understand the architecture decisions that keep systems maintainable long-term. HOW I WORK I use AI coding tools (Claude Code, Cursor) as my primary development workflow. This means I ship faster than a traditional developer, but with the fundamentals to know when the AI is wrong, what will break at scale, and when to override it. I communicate clearly, translate vague requirements into concrete plans, and work reliably in distributed async teams. I've led client-facing conversations, written technical specs from rough briefs, and taken full ownership of delivery. STACK AT A GLANCE Frontend: React, Next.js, TypeScript, Vue.js, WordPress, Elementor Backend: .NET/C#, Node.js, PHP/Laravel Databases: SQL Server, PostgreSQL, MongoDB, MySQL AI/LLM: Claude, GPT, prompt engineering, evaluation pipelines, MCP Auth: OAuth, OIDC, Clerk, Firebase Cloud: Azure, AWS, Docker, Vercel Other: OData, REST APIs, Git, CI/CD If you're building something that needs to work, scale, and last let's talk.

  • JSON
  • CSS 3
  • React
  • Node.js
  • HTML5
  • JavaScript
  • WordPress
  • GitHub
  • PHP
  • WordPress Theme
  • WooCommerce
Ivan G.

Almaty, Kazakhstan

$25/hr
5.0
72 jobs

Having a decade of mastery in 🔸 Front-end Development: JavaScript, React.js, Next.js, HTML5, CSS3, Bootstrap, Tailwind CSS, jQuery 🔸 Back-end Development: Node.js, PHP, MySQL, SQL Server, MongoDB, Redis, Apps Script, Ruby 🔸 CMS & Frameworks: WordPress, Joomla, Codeigniter, Laravel, Express.js, etc 🔸 Data Scraping & Automation: Web scraping, Data extraction, API scraping, Puppeteer, Playwright 🔸 Google Apps Script, Google Spreadsheets API, Google Sheets 🔸 Cloud Platforms & Services: Google Cloud Platform (GCP), Firebase, Amazon Web Services (AWS) Result oriented developer, able to quickly grasp new technologies. I love to help you solve your web related problems: building, fixing, migrating, customizing, optimizing.

  • PHP
  • Node.js
  • WordPress
  • Web Development
  • JavaScript
  • Firebase
  • Ruby
  • MongoDB
  • PostgreSQL
  • Supabase
  • Next.js
  • React
  • Joomla
  • Google Apps Script
  • Web Scraping
Niroyan K.

Etobicoke, Canada

$12/hr
4.7
24 jobs

Hey Boss.. I know , are you looking for something right ? So first, go and check out my recent projects and client feedback. Do you think I’m a good fit for this project? If yes, let me introduce myself. Full-Stack Web Developer | React | Next.js | TypeScript | Expresses JS | MongoDB | Firebase | AI & Cloud I’m a Full-Stack Web Developer focused on building fast, modern, responsive, SEO-friendly, and scalable web applications for startups, agencies, and businesses. I’ve also worked on AI applications, SaaS products, dashboards, CMS websites, authentication systems, API integrations, landing pages, portfolios, and custom business applications. 💻 Tech Stack Frontend: React, Next.js, Astro.js, TypeScript, JavaScript, HTML5, CSS3, Tailwind CSS, SCSS, Bootstrap Backend & Database: Node.js, Python, Supabase, Firebase, PostgreSQL, MongoDB APIs & CMS: REST APIs, GraphQL, Sanity CMS, third-party API integrations Animation & UI: Framer Motion, GSAP, responsive design, reusable component systems, micro-interactions Development & Deployment: Git, GitHub, Vercel, Cloudflare, CI/CD workflows AI: OpenAI API integration, AI-assisted development, AI-powered application features 🎯 What I Build SaaS • Landing Pages • Business Websites • Dashboards • AI Applications • E-commerce • Portfolio Websites • CMS Websites • Custom Web Apps 🛠 Services Frontend Development • Full-Stack Development • API Integration • UI/UX Implementation • Figma to Code • Responsive Design • SEO Optimization • Performance Optimization • Authentication • Database Design • CMS Development • OpenAI API Integration • Bug Fixing • Website Maintenance Why Work With Me? ✓ Pixel-perfect implementation ✓ Clean, reusable, scalable code ✓ Mobile-first responsive development ✓ Strong React/Next.js experience ✓ Smooth Framer Motion & GSAP animations ✓ SEO-focused architecture ✓ Performance and Core Web Vitals optimization ✓ Fast communication and regular updates ✓ Git/GitHub-based development workflow ✓ Reliable, on-time delivery I’m comfortable joining both new builds and existing codebases, understanding the architecture quickly, fixing issues, implementing new features, and shipping production-ready updates. Keywords: React Developer, Next.js Developer, Full-Stack Developer, Frontend Developer, JavaScript Developer, TypeScript Developer, Astro Developer, Tailwind CSS Developer, SaaS Developer, AI Developer, Figma Developer, Landing Page Developer, Dashboard Developer, API Integration, Supabase Developer, Firebase Developer, Node.js Developer, Python Developer, SEO Optimization.

  • JSON
  • Landing Page
  • Website
  • Responsive Design
  • Web Development
  • HTML5
  • JavaScript
  • Web Design
  • Front-End Development
  • React
  • Next.js
  • Tailwind CSS
  • SEO Strategy
  • API
  • Node.js
Priyanshu R.

Indore, India

$25/hr
4.9
693 jobs

I create lightweight, interactive Lottie and Rive animations for SaaS products and mobile apps. 600+ projects delivered. From splash screens to complex state-machine UIs — I ship production-ready .json and .riv files that developers. Top Rated on Upwork | Top 10% | Trusted by 600+ clients across North America, Europe, and Asia. Whether you need a crisp app onboarding animation or a compelling explainer video that drives conversions — I bring both the motion design expertise and the storytelling instinct to make it land. Clients include Toyota, Vivo, Somany Bathware, and 600+ SaaS, fintech, e-commerce, and ed-tech teams. What I Create ⚡ Lottie Animation — Lightweight, dev-ready Lottie JSON files for web and mobile apps. I create onboarding flows, loading animations, micro-interactions, UI state transitions, empty-state illustrations, success/error feedback animations, and in-app storytelling sequences. Every file is optimized for size and performance — typically under 50KB — and tested across platforms before delivery. 🎮 Rive Animation — Interactive Rive components and character animations with real-time state machines. I build toggle animations, interactive buttons, animated icons, onboarding characters, and gamified UI elements that respond to user input. Built for performance, designed for seamless developer handoff with clean state machine architecture. 🎬 Explainer Videos — Script-to-screen explainer videos for SaaS, fintech, healthcare, and product launches. I handle concept development, scriptwriting support, storyboarding, illustration, voiceover direction, and final animation. Every video is designed to simplify complex ideas, increase landing page conversions, and reduce customer support load. Styles include 2D character animation, flat design motion graphics, whiteboard animation, and isometric explainer videos. 🎨 Motion Graphics & After Effects — Logo reveals, brand intros/outros, social media video ads, product launch teasers, event promos, animated infographics, and kinetic typography. Whether it's a 5-second logo sting or a 90-second ad campaign, I match your brand guidelines and deliver broadcast-quality motion design. 📱 UI/UX Animation & Prototyping — App transition animations, navigation flows, scroll-triggered effects, and interactive prototypes. I bridge the gap between design and development by creating animations that developers can implement pixel-perfectly using Lottie, Rive, or CSS/SVG specs. Industries I Work With I've delivered animation projects across SaaS, fintech, e-commerce, ed-tech, healthcare, real estate, logistics, cybersecurity, HR tech, and consumer brands. This cross-industry experience means I understand how to communicate complex workflows, technical products, and abstract services visually. My Process — Built for Async, Remote Teams 1. Discovery & Concept Alignment — I review your brief, ask targeted questions, and define the creative direction, audience, and goals before any design work begins. 2. Script & Storyboard — For explainer videos, I collaborate on the script or write from scratch, then deliver an illustrated storyboard for approval. For UI animations, I share motion briefs or style frames. 3. Animation Production — I animate in After Effects, Rive, or directly for Lottie export depending on the deliverable. You'll see progress at key checkpoints — no surprises at the end. 4. Feedback & Revisions — Structured revision rounds with clear communication. I respond to feedback within 0–4 hours during working days. 5. Final Delivery — Production-ready files delivered in the format your team needs: Lottie JSON, Rive files, After Effects projects, MP4, MOV, GIF, or WebM. All assets are optimized for fast loading, smooth playback, and easy integration. Tools & Technical Stack Adobe After Effects, Bodymovin/Lottie, Rive (with state machines), Adobe Illustrator, Spline, Photoshop, Audition. I'm comfortable working alongside developers using React, Flutter, Swift, and Kotlin — and I ensure every animation file integrates cleanly into your existing tech stack. Why Clients Keep Coming Back → I don't just animate — I think about why something moves. Every animation serves a purpose: guiding attention, simplifying a concept, increasing engagement, or driving a specific user action. → I communicate clearly and proactively. You'll never have to chase me for updates. → I deliver on time, every time. Deadlines are non-negotiable for me. → I optimize for the real world — file size, load time, cross-platform compatibility, and developer handoff are part of my standard process, not afterthoughts. 📩 Send me your project brief — I'll respond with a clear plan, timeline, and estimate within 4 hours. My Expertise: Lottie Animation, Rive Animation, Motion Graphic Design, UI Animation, Motion Design, Gif, SVG Animation, Explainer Videos, SaaS Animated Videos, Onboarding animation, Icon Animation

  • JSON
  • Lottie
  • GIF
  • SVG
  • UI Animation
  • Motion Design
  • Motion Graphics
  • Interactive Design
  • Animated GIF Design
  • Animated GIF
  • Character Animation
  • Adobe After Effects
  • 2D Animation
  • Interaction Design
  • Splash Screen
  • Interactive Prototype
  • Animated Explainer
  • Video Production
  • Explainer Video
  • Mobile App Design

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JSON FAQs

What is JSON?

JSON (JavaScript Object Notation) is a data interchange format that has vastly improved server-to-browser communications—especially when it comes to AJAX. It’s a language that’s similar to XML, syntactically identical to JavaScript code, and the fastest data-interchange format to be used with AJAX (Asynchronous JavaScript + XML), making it not far behind HTML when it comes to skills no front-end developer should go without.

JSON is a syntax designed to store and move data that’s sent between server and browser. It’s similar to a markup language in its syntax and how it’s used, but it’s not a markup language at its core. If you think of how XML functions in the scheme of a site—XML describes elements of data, while HTML displays that data—JSON does the same thing, just in a more streamlined way, both for the developer and the browser.

Why hire a JSON specialist?

A front-end developer who specialists in JSON can help you to create interactive, high-performance sites and apps. 

JSON was the first format that allowed servers and browsers to communicate without a browser plug-in like Flash or Java. But where JSON really shines—and sets the standard—is how it functions within AJAX operations. AJAX essentially allows parts of a web page to be updated without requiring a full-page refresh, something that vastly changed the way users interact with web applications. It immediately solved problems that were caused by limited bandwidth, prevented server overload, and kept things from slowing down in the app.

AJAX was originally created in the mid-2000s with XML as its data interchange format. In that first model, after a page was loaded, new data could be called up from the server using XML as the data interchange format. JSON has improved the data retrieval process by being front-end compatible by nature with its JavaScript roots. With JSON and JSON Web Services, AJAX runs faster—it’s instantaneous and highly efficient.

JSON’s core differentiator is that it’s written in JavaScript syntax, but it’s text-only. This allows it to logically skip a front-end step: Whereas XML requires a parser to be read by a JavaScript program, JSON doesn’t require any extra software. It’s a subset of JavaScript, and so it’s compatible with the front end, right off the bat. A JavaScript program will convert JSON elements directly into JavaScript objects.

Like XML, JSON:

  • Is “self-describing,” meaning humans can read it
  • Uses hierarchical values
  • Can be read by many programming languages
  • Is able to be “fetched” by an XMLHttpRequest

How JSON is different than XML:

  • Doesn’t require an end tag and won’t “break” without one
  • Is shorter to read and quicker to write
  • Uses arrays, which are logical ways to bulk similar data formats in an element