Hire the Best Backend Rest API Freelancers
in the United States

More than 3,000 reviews on G2
Rating is 4.5 out of 5.
4.5/5
of Upwork by G2 peer reviewers
Sen C.

Tacoma, Washington

$40/hr
5.0
64 jobs

If your data is stuck in the wrong system, in messy files, or behind an awkward API, I can help. I turn complex data problems into working systems and usable deliverables. I help clients move data between platforms, automate manual work, clean up unreliable exports, and build workflows that save time and reduce errors. Whether the deliverable is a program they can keep using, or a clean CSV, Excel file, report, or database, I can make it happen. Most of my work is API integrations, ETL pipelines, backend automation, data processing, and data migrations. I'm at my best when the problem is not clean or perfectly defined. I'll solve that problem first. I build data workflows that are meant to hold up in real use. I work with complex APIs, big JSON or XML data files, elaborate schema, folders full of CSV and Excel files, and large datasets where correctness matters. The result is a cleaner dataset, a dependable program, or a responsive and well-designed workflow. If you need a dependable program, a solid new system, or a clean final dataset, I can help.

  • REST API
  • API
  • Data Science
  • Python
  • MySQL
  • Data Processing
  • pandas
  • PostgreSQL
  • JSON
  • SQLite
  • Data Cleaning
  • Jupyter Notebook
  • CSV
  • SQL
  • XML
Jacob C.

New York, New York

$80/hr
4.4
56 jobs

I build the kind of WordPress and backend systems that don't fit into a page builder, such as custom plugins, REST API integrations, MySQL-backed application logic, and the engineering layer that ties the rest of a business's stack together. Most of my clients come to me when: ◆ Their site is too complex for junior developers ◆ Plugins don't do what they need and someone has to write real code ◆ They need a system, not just a website ◆ Performance is poor and things keep breaking ◆ They need a senior engineer to own the technical side --- Proven Track Record --- "Jacob is 100% the best freelancer I've ever hired." ⎻ Andrew Epprecht, Phase5Analytics "You're an incredible WordPress developer… now our site is lightning fast." ⎻ Denise Deverelle, Multifamily Utility Company "Went above and beyond. One of my best experiences on Upwork." ⎻ Ryan Jordan, XNEffect "Gets things done faster than any developer I've ever worked with. And done well." ⎻ Chris Johnson, CTO, CrisisTextLine --- What I Do Best --- Custom WordPress Development ◆ Custom plugins built around specific business logic ◆ Custom Gutenberg blocks and modern block themes ◆ WooCommerce customizations and integrations ◆ Headless / API-driven WordPress architectures ◆ Performance, Core Web Vitals, and security hardening API & Integration Development ◆ REST API design and third-party API integrations ◆ Payment gateways and external service connections ◆ Custom internal tools and admin dashboards ◆ Data synchronization and workflow automation ◆ Bridging WordPress with external SaaS, ERPs, and CRMs Backend Engineering ◆ PHP application development beyond CMS contexts ◆ MySQL schema design and query optimization ◆ Refactoring legacy codebases into something maintainable ◆ Custom business logic and workflow engines ◆ Production-grade architecture for systems that need to scale --- Who I Work Best With --- I'm a great fit if you: ◆ Need a senior engineer who can take real ownership of the technical side ◆ Have a growing business with real technical challenges, not a side project ◆ Care about code quality, maintainability, and long-term stability ◆ Want a long-term technical partner, not the cheapest hourly rate I work with a small number of clients at a time, so each engagement gets the attention it deserves. --- Who I'm Not a Fit For --- I'm probably not the right developer if: ◆ You're looking for someone to wire up Elementor, Divi, or another page builder ◆ Your project is a simple theme tweak or one-off plugin installation ◆ You want the lowest hourly rate available on Upwork ◆ You need design, copywriting, or UX work That's not a knock on those projects. They just aren't the kind of work I'm built for, and there are excellent freelancers on Upwork who specialize in them who'll be a better fit than I would. --- How I Work --- I work best on ongoing engagements, such as monthly retainers, multi-month projects, or technical-lead partnerships where I can take real ownership of the codebase. Short, one-off task gigs usually aren't a good fit on either side, though I'll occasionally take on a well-scoped project as a working trial. I communicate clearly, set realistic timelines, and take full responsibility for my work. --- Let's Talk --- If you need a senior developer who can actually solve hard problems, in WordPress, in PHP, or in custom backend systems, click the "Invite to Job" button and tell me what you're trying to accomplish.

  • REST API
  • WordPress Development
  • WordPress Customization
  • Plugin Development
  • WooCommerce
  • API Integration
  • PHP
  • JavaScript
  • MySQL
  • Performance Optimization
  • WordPress Plugin
  • Theme Development
  • WordPress Optimization
  • WordPress Security
  • WordPress e-Commerce
Muhammad L.

Orlando, FLORIDA

$15/hr
5.0
314 jobs

With 10+ years of experience in software development and 5+ years as a Top Rated freelancer on Upwork, I help startups, founders, and businesses build scalable digital products using Bubble, AI automation, and data-driven dashboard solutions. I specialize in turning ideas into production-ready applications with fast execution, clean architecture, and business-focused functionality. Core Expertise: Bubble Development & No-Code Solutions * Custom Bubble web applications * SaaS MVP development * Internal business tools & client portals * Workflow automation & scalable database architecture * Responsive UI/UX implementation * Marketplace, CRM, and platform development AI Integration & Automation * OpenAI, ChatGPT, Claude, Gemini integrations * AI powered workflows & automation systems * AI chat assistants & custom AI tools * API integrations & third-party automation * CRM and operational process automation * AI enhanced business applications Power BI & Dashboard Development * Interactive Power BI dashboards * KPI reporting & business intelligence solutions * Data visualization & analytics systems * Executive reporting dashboards * Operational and sales performance tracking * Automated reporting workflows Full Stack Development * Next.js, React.js, Node.js * React Native mobile applications * REST API integration * Custom backend logic & scalable architectures Why Clients Work With Me: * Top Rated Upwork freelancer with long-term client relationships * Strong understanding of both business operations and technology * Fast delivery without compromising scalability or quality * Clear communication and structured project management * Focused on building systems that improve efficiency and growth Recent Projects Include: * AI powered SaaS applications using Bubble * Business intelligence dashboards in Power BI * CRM and workflow automation systems * Marketplace and service platforms * AI chat assistants trained on custom business data * Operational dashboards and reporting systems If you need a Bubble expert who can combine AI automation, Power BI dashboards, and scalable product development into one streamlined solution, let's discuss your project.

  • Front-End Development
  • Bubble.io
  • Microsoft Power BI
  • Back-End Development
  • React Native
  • Next.js
  • React
  • Data Warehousing
  • Data Visualization
  • SaaS Development
  • AI App Development
Quentin H.

Girard, Ohio

$75/hr
4.9
59 jobs

I've spent 11 years working with clients of all sizes across a lot of different industries. That breadth means I can adapt quickly to just about any app idea and pick up new domains fast. I know the grind of building out a first MVP and I know how to jump into an existing codebase and find the path of least resistance to get it fixed. Both sides of that equation. What I like most is looking at the long-term picture - planning different stages, thinking through feature releases, watching an app grow. Most of my best client relationships have lasted years because of that. It's good for them and honestly it represents stability for me too. That alignment tends to produce better work. If you're looking for someone to own the mobile side of your product and stick around, send me a message. — Quentin H.

  • REST API
  • Swift
  • SwiftUI
  • Objective-C
  • UIKit
  • Kotlin
  • Java
  • Android
  • iOS Development
  • Mobile App Development
  • Firebase
  • SQL
  • Software Architecture
  • UI/UX Prototyping
  • Code Refactoring
Mohid Amin J.

San Diego, California

$35/hr
5.0
3 jobs

Awarded Rising Talent on Upwork (awarded to less than 5%) with a Computer Science degree. One of the fastest-growing AI Automation and full-stack profiles on the platform. A $2M/year e-commerce brand recovered $34k in 60 days after I replaced their manual cart follow-up with an AI Automation workflow. Zero manual work remaining. That's the kind of outcome I build toward, and not just automation, but AI automation that pays for itself within weeks. -78+ projects delivered -Clients generating $1M+ MRR -Fortune 500 experience -MVPs shipped in under 2 weeks 𝗥𝗲𝗰𝗲𝗻𝘁 𝗥𝗲𝘀𝘂𝗹𝘁𝘀: -𝗘-𝗖𝗼𝗺𝗺𝗲𝗿𝗰𝗲: Cart recovery AI Automation for a $2M/year brand. Recovered $34k in 60 days, manual follow-up reduced to zero -𝗠𝗮𝗿𝗸𝗲𝘁𝗶𝗻𝗴 𝗔𝗴𝗲𝗻𝗰𝘆: Lead qualification and automated onboarding on GHL and n8n. Onboarding reduced from 3 days to 4 hours, capacity up 60% without hiring -𝗥𝗲𝗮𝗹 𝗘𝘀𝘁𝗮𝘁𝗲: AI lead follow-up and open house automation using Zapier, Airtable, and OpenAI GPT. Appointments up 40%, 15 hours of manual outreach eliminated weekly -𝗟𝗲𝗴𝗮𝗹 𝗮𝗻𝗱 𝗙𝗶𝗻𝗮𝗻𝗰𝗲: Documentation automation and lead qualification using n8n and LLM Implementations. 20 hours saved weekly, onboarding errors reduced 80% -𝗔𝗜 𝗔𝗽𝗽: LangChain, OpenAI GPT, and Pinecone replaced a $15k/month manual process with an AI-powered workflow running in under 3 seconds -𝗡𝗼-𝗖𝗼𝗱𝗲 𝗠𝗩𝗣: Full MVP in 11 days using Bubble and API integration resulting in client closing first paying customer before launch 𝗪𝗵𝗮𝘁 𝗜 𝗕𝘂𝗶𝗹𝗱: -𝗔𝗜 𝗔𝗴𝗲𝗻𝘁𝘀 𝗮𝗻𝗱 𝗔𝗜 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗶𝗼𝗻/𝗪𝗼𝗿𝗸𝗳𝗹𝗼𝘄 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗶𝗼𝗻: Custom AI Agents and end-to-end automated workflows on n8n, Make, LangChain, Claude, and OpenAI GPT qualifying leads, running operations, and eliminating manual steps through custom API integrations, webhooks, and REST connections. -𝗔𝗜 𝗔𝗽𝗽 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁 𝗮𝗻𝗱 𝗟𝗟𝗠 𝗜𝗺𝗽𝗹𝗲𝗺𝗲𝗻𝘁𝗮𝘁𝗶𝗼𝗻𝘀: Full-stack AI applications, internal AI dashboards, and AI-powered workflows built with Next.js, Node.js, Python, and LangChain, RAG pipelines, Pinecone vector databases, LLM orchestration in production -𝗩𝗼𝗶𝗰𝗲 𝗔𝗜 𝗔𝗴𝗲𝗻𝘁𝘀: AI-powered voice agents on Vapi and ElevenLabs handling inbound calls, qualifying leads, and booking appointments -𝗡𝗼-𝗖𝗼𝗱𝗲 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁 𝗮𝗻𝗱 𝗠𝗩𝗣𝘀: MVPs in under 2 weeks using Bubble, Lovable, and Supabase hence validate fast before you overspend -𝗖𝗥𝗠 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗶𝗼𝗻 𝗮𝗻𝗱 𝗖𝗥𝗠 𝗜𝗻𝘁𝗲𝗴𝗿𝗮𝘁𝗶𝗼𝗻: GoHighLevel, HubSpot Automation, Airtable, and custom CRM workflows that consolidate fragmented data and surface revenue you didn't know you were losing -𝗔𝗣𝗜 𝗜𝗻𝘁𝗲𝗴𝗿𝗮𝘁𝗶𝗼𝗻: Custom API integrations across REST APIs, webhooks, and third-party platform built clean and built to last -𝗠𝗮𝗿𝗸𝗲𝘁𝗶𝗻𝗴 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗶𝗼𝗻: Automated outreach and lead nurturing across GHL, HubSpot, and Airtable so no lead goes cold -𝗣𝗿𝗼𝗺𝗽𝘁 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴 𝗮𝗻𝗱 𝗔𝗜 𝗖𝗼𝗻𝘀𝘂𝗹𝘁𝗶𝗻𝗴: Structured prompt systems and AI Orchestration that make LLMs reliable in production 𝗧𝗼𝗼𝗹𝘀/𝗧𝗲𝗰𝗵 𝗦𝘁𝗮𝗰𝗸: 𝗔𝗜 𝗮𝗻𝗱 𝗟𝗟𝗠: Claude, OpenAI GPT, LangChain, Pinecone, Vector Database, RAG pipelines, AI Orchestration, LLM Implementations 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗶𝗼𝗻: n8n, Make, Zapier 𝗡𝗼-𝗖𝗼𝗱𝗲: Bubble, Lovable, Airtable, no-code development, MVPs 𝗖𝗥𝗠: GoHighLevel, HubSpot Automation, CRM Automation, CRM integration, CRM consolidation 𝗙𝘂𝗹𝗹-𝗦𝘁𝗮𝗰𝗸: Next.js, Node.js, Python, Supabase, PostgreSQL, API integration 𝗩𝗼𝗶𝗰𝗲 𝗔𝗜: Vapi, ElevenLabs, voice AI agents Not every problem needs a new AI Agent. Part of my job is helping you decide what not to build so budget goes toward what actually moves the needle. Message me with what you're trying to automate or build. If it's a fit, I'll tell you exactly how I'd approach it before we begin. 𝗘𝗫𝗣𝗘𝗥𝗧𝗜𝗦𝗘: AI Automation | AI Agents | No-Code Development | Airtable | Make com | n8n | LLM Implementation | Workflow Automation | API Integration | GHL Automation | Gohighlevel expert Business Process Automation | Voice AI Agents | Vapi | ElevenLabs | CRM Automation | GoHighLevel | HubSpot Automation | Marketing Automation | Prompt Engineering | AI Consulting | AI Orchestration | LangChain | Pinecone | Vector Database | RAG Pipelines | Bubbleio | Lovable | Next.js | Node.js | Python | Supabase | MVP Development | AI App Development | AI Chatbot | OpenAI GPT | Claude | Internal AI Dashboard | no-code development | Bubble freelancer | MVP creation | startup MVPs | API integrations | SaaS applications | artificial intelligence | internal tools | Gohighlevel Pro | custom SaaS solutions | AI integration | no-code SaaS | App development | business automation tools | no-code AI | scalable MVPs | rapid app development | Bubble app builder | SaaS product development | no-code solutions | Bubble developer | app prototyping | business process automation | SaaS startup

  • Automation
  • AI App Development
  • API Integration
  • n8n
  • Zapier
  • Bubble.io
  • Make.com
  • AI Agent Development
  • Airtable
  • Next.js
  • Supabase
  • Web Development
  • JavaScript
  • Python
  • Artificial Intelligence
  • SaaS Development
  • Prompt Engineering
  • AI Chatbot
  • AI Implementation
  • No-Code Development
Muhammad T.

Lynnwood, Washington

$30/hr
4.9
68 jobs

✅ Custom WordPress Websites That Convert Visitors Into Customers ✅ WooCommerce Stores Optimized for Sales & Growth ✅ AI Agents & Business Automation Solutions That Save Time and Increase Efficiency I'm Muhammad Tahir, a Top-Rated WordPress Developer with 6+ years of experience building high-performance websites, custom WordPress solutions, WooCommerce stores, and AI-powered automation systems. I help businesses create fast, scalable, and conversion-focused digital experiences using WordPress, Elementor Pro, WooCommerce, PHP, APIs, and AI technologies. 𝐖𝐡𝐚𝐭 𝐈 𝐂𝐚𝐧 𝐇𝐞𝐥𝐩 𝐘𝐨𝐮 𝐖𝐢𝐭𝐡 ✔ WordPress Development ▪️ Custom WordPress websites ▪️ Theme customization ▪️ Plugin development ▪️ Custom functionality ✔ Elementor Pro Expert ▪️ Pixel-perfect Elementor websites ▪️ Landing pages ▪️ Conversion-focused design ▪️ Mobile-responsive layouts ✔ WooCommerce Development ▪️ Custom WooCommerce stores ▪️ Subscription and membership websites ▪️ Checkout optimization ▪️ Payment gateway integration ▪️ Product and inventory management ✔ AI Agents & Automation ▪️ ChatGPT integration ▪️ AI customer support agents ▪️ Knowledge-base AI assistants ▪️ OpenAI API integration ▪️ Workflow automation ▪️ Business process automation ✔ API Development & Integration ▪️ REST API development ▪️ Third-party integrations ▪️ CRM integrations ▪️ Marketing platform integrations ▪️ Custom data synchronization ✔ Website Performance & Security ▪️ Core Web Vitals optimization ▪️ Speed optimization ▪️ Security hardening ▪️ Malware cleanup ▪️ Hosting optimization ✔ SEO & Technical Optimization ▪️ On-page SEO ▪️ Technical SEO ▪️ Schema implementation ▪️ Website audits ▪️ Search engine visibility improvements 𝐖𝐡𝐲 𝐂𝐥𝐢𝐞𝐧𝐭𝐬 𝐖𝐨𝐫𝐤 𝐖𝐢𝐭𝐡 𝐌𝐞 ✔ Top-Rated Upwork Freelancer ✔ 100% Client-Focused Approach ✔ Clean, Maintainable Code ✔ Fast Communication & Reliable Delivery ✔ Long-Term Support & Consultation ✔ Business-Oriented Solutions That Deliver Results 𝐑𝐞𝐜𝐞𝐧𝐭 𝐂𝐥𝐢𝐞𝐧𝐭 𝐅𝐞𝐞𝐝𝐛𝐚𝐜𝐤 "The website he developed exceeded our expectations and significantly improved our online sales." Whether you need a custom WordPress website, WooCommerce store, Elementor Pro redesign, AI-powered chatbot, automation workflow, or API integration, I can help turn your vision into a scalable solution. Let's discuss your project and build something exceptional. Muhammad Tahir WordPress Expert | Elementor Pro | WooCommerce | AI Agent & Automation

  • API Development
  • PHP
  • JavaScript
  • WordPress
  • WordPress Website
  • WordPress Theme
  • WordPress e-Commerce
  • Elementor
  • WooCommerce
  • API Integration
  • WordPress Multisite
  • WordPress Landing Page
  • WordPress Website Design
  • WordPress Development
  • WordPress SEO Plugin
  • User Experience Design
  • SEO Performance
  • Ecommerce Website Development
  • Custom Web Design
  • Website Performance Optimization

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