You will get OAuth Integration Setup | API Authentication Developer Portal Configuration
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Project details
As a full stack developer I implement OAuth authentication flows and API integrations across production platforms — connecting web applications to Google, Meta, Stripe, GoHighLevel, and third-party services via secure token-based and session-based authentication.
This service covers OAuth app registration and configuration across developer portals, redirect URI setup, permission scope configuration, Client ID and Secret management, and full documentation of every integration. I've configured OAuth flows for Meta Ads API, Google APIs, Stripe webhooks, and Brevo — all running in production SaaS platforms with real users.
As a full stack developer I understand both sides of the integration — the developer portal configuration and the application code that consumes it. Every setup is documented cleanly with credentials, app URLs, status, and notes so your team has full visibility and control from day one.
Stack: Next.js, Node.js, REST API, OAuth 2.0, JWT, NextAuth, Vercel.
This service covers OAuth app registration and configuration across developer portals, redirect URI setup, permission scope configuration, Client ID and Secret management, and full documentation of every integration. I've configured OAuth flows for Meta Ads API, Google APIs, Stripe webhooks, and Brevo — all running in production SaaS platforms with real users.
As a full stack developer I understand both sides of the integration — the developer portal configuration and the application code that consumes it. Every setup is documented cleanly with credentials, app URLs, status, and notes so your team has full visibility and control from day one.
Stack: Next.js, Node.js, REST API, OAuth 2.0, JWT, NextAuth, Vercel.
Programming Languages
HTML & CSS, JavaScript, TypeScriptCoding Expertise
Security, DesignWhat's included
| Service Tiers |
Starter
$300
|
Standard
$700
|
Advanced
$1,500
|
|---|---|---|---|
| Delivery Time | 2 days | 5 days | 10 days |
Number of Revisions | 1 | 2 | 2 |
Design Customization | - | - | - |
Content Upload | - | - | - |
Responsive Design | - | - | - |
Source Code | - | - | - |
14 reviews
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MD
Matt D.
Jun 15, 2026
30 minute consultation
Working with Svitlana was a great experience. She has a real talent for breaking down complex topics and explaining them in simple, easy-to-understand terms. Beyond just answering my questions, she proactively came up with solutions to current problems and suggested smart alternatives that worked even better than what I'd originally planned. She helped me get a much clearer handle on my software and GHL account. I'd happily work with her again and highly recommend her.
CG
Carter G.
May 19, 2026
Lead Full-Stack Developer | Next.js, React, Node.js, PostgreSQL
Svitlana has been exceptional to work with. She is highly responsive, detail oriented, and consistently focused on solving problems rather than creating them. She took ownership of both CarCupid and K9Cupid quickly, communicated clearly throughout the process, and handled complex technical and UX challenges with professionalism and accountability.
What stood out most was her ability to think beyond simply completing tasks. She actively contributed ideas to improve the products, streamline workflows, and create a better user experience overall. Her work quality, reliability, and strategic mindset made her feel more like a true partner than just a developer. I would confidently recommend her to anyone building a serious long term project.
What stood out most was her ability to think beyond simply completing tasks. She actively contributed ideas to improve the products, streamline workflows, and create a better user experience overall. Her work quality, reliability, and strategic mindset made her feel more like a true partner than just a developer. I would confidently recommend her to anyone building a serious long term project.
HS
Hussain S.
May 9, 2026
Technical Handover Specialist
GP
Gerard P.
Apr 21, 2026
Roadmapping and Technical Analysis of Feature complexitity using Ai tools
Svitlana is a joy to work with. She will consistently exceed your expectations and surprise you with her speed. I plan to continue working with her because she's great.
DO
Donnie O.
Mar 31, 2026
Automation Specialist for Stripe + GoHighLevel + Google Sheets Integration
I rarely leave reviews like this, but Svitlana genuinely earned it, and then some. I hired her to build a complex CRM inside Go High Level, and what she delivered went so far beyond my expectations, so much that I felt compelled to send her a $200 tip before I even wrote this. That's not something I've ever done before on Upwork. The build itself is sophisticated (custom pipelines, automations, workflows) the kind of thing that can easily go sideways with someone who doesn't truly know the platform. Svitlana navigated Go High Level with ease. She asked the right questions upfront, communicated clearly throughout, and delivered clever logical work that makes perfect sense when I looked under the hood. No hand-holding required. No back-and-forth to fix sloppy work, just clean results. If you're looking for a Go High Level expert who will treat your project with commitment and care, stop looking. Hire Svitlana. :)
About Svitlana
Full Stack Developer | SaaS Developer | Dashboard Developer
100%
Job Success
Bexhill-on-Sea, United Kingdom - 8:52 pm local time
I am a full stack developer, SaaS developer, and dashboard developer in the UK — Top Rated Plus on Upwork, top 3% globally. I build systems that run businesses — working platforms with real users, real transactions, and business impact.
As a full stack developer I own the entire stack — PostgreSQL design, Node.js and Nest.js backend, React and Next.js frontend, REST API integrations, Stripe payments, and Vercel deployment. Need a full stack developer, SaaS developer, or dashboard developer who owns the technical side — architecture, payments, integrations, deployment, security? Let's talk.
My recent full stack developer work includes a SaaS platform for trades businesses — a Next.js app with job management, client records, quoting, and role-based access. I also built a B2B admin dashboard across PostgreSQL, Node.js, and React — the tool a team of 20 depends on every day.
SaaS developer. Multi-tenant. Production-ready.
As a SaaS developer I delivered a multi-tenant SaaS starter on Next.js with Stripe subscriptions, PostgreSQL via Neon, role-based access, billing portal, and team invites — fully documented, repo transferred on handover. I led a full platform rebuild migrating a legacy PHP and WordPress stack to a modern Next.js and Nest.js architecture — 40% improvement in user engagement post-launch.
Backend developer. Nest.js. PostgreSQL.
As a backend developer I build production Nest.js and Node.js APIs on PostgreSQL with TypeScript end to end. My recent backend work includes a Nest.js and PostgreSQL backend for a raffle SaaS platform — secure JWT authentication, OAuth provider integration, password reset and recovery flows, and a clean REST API layer for a Next.js and React frontend. Backend work that has to be correct: every endpoint authenticated, every role enforced, every PostgreSQL query written with isolation in mind.
Security audit. Supabase RLS. Multi-tenant isolation.
As a full stack developer and technical consultant I run pre-launch security audits for SaaS founders — the review that must happen before real customer data goes live. My security audit work covers Supabase Row Level Security (RLS), multi-tenant isolation, PostgreSQL policy design, and authentication flows. I've audited a multi-tenant property maintenance SaaS on Supabase, reviewing RLS policies and tenant data separation. On another platform I found RLS policies that lived only in discarded migrations, never applied to the database — the silent multi-tenant data leak an audit catches before a breach. If you're a SaaS founder on Supabase, Next.js, or PostgreSQL and aren't certain your tenant data is isolated, that's the audit I do.
Dashboard developer. Data that changes decisions.
As a dashboard developer with a KendoReact commercial licence I build enterprise-grade interfaces standard React developers can't replicate — advanced data grids, real-time charts, and complex forms that perform under load. My dashboard developer portfolio includes a marketing analytics dashboard with AI insights that cut campaign review time by 60% for a British agency, and a SaaS analytics dashboard with Chart.js and PDF export that replaced a weekly manual reporting process.
Integrations. Authentication. Infrastructure.
OAuth integration and API authentication developer portal config — credential flows for Google, GitHub, and custom providers using NextAuth, Nest.js, and JWT. Google Tag Manager setup with GA4 and Meta Pixel across complex Next.js applications, with GTM as the management layer for non-technical teams. Transactional email wired to Resend and Brevo, plus Next.js blog and CMS setup with Sanity Studio.
Stripe. Payments. Automation.
Payment systems are a core part of my full stack developer work. I built a Stripe internal payment interface with role-based access on Next.js — PaymentIntent flow, full audit log, zero card data stored. I delivered Stripe payment integration with webhooks and subscription billing handling upgrades, downgrades, and failed payment recovery. I wire Stripe with Make, GoHighLevel, and Google Sheets so every transaction triggers the right email, CRM tag, and notification.
Technical consultant. Architecture. Audit.
I work as a technical consultant for non-technical founders. My tech stack and architecture audit with written report shows founders what they have, what's broken, and what to build next — vendor selection, architecture decisions, developer estimate review, security and multi-tenant isolation review, and a roadmap.
As a Next.js performance optimization specialist I audit and improve Lighthouse and PageSpeed results — render-blocking resources, Core Web Vitals, and measurable gains for user experience and search ranking.
Next.js · React · Node.js · Nest.js · PostgreSQL · Supabase · TypeScript · JavaScript · REST API · Stripe · Kendo UI · Sanity · Make · GoHighLevel · Vercel · NextAuth · JWT · OAuth · RLS · Chart.js · GA4 · Meta
Steps for completing your project
After purchasing the project, send requirements so Svitlana can start the project.
Delivery time starts when Svitlana receives requirements from you.
Svitlana works on your project following the steps below.
Revisions may occur after the delivery date.
Provider List & Access
I review your full list of providers, request necessary access to your developer portals, and create a structured tracking spreadsheet before starting any configuration.
OAuth App Registration
I register your application on each provider portal — app name, branding, redirect URIs, permission scopes, and visibility settings configured precisely to your requirements