Vetted full stack & backend engineers capable of delivering Stripe solutions
Khmelnytskyi, Ukraine
Full-Stack Developer, Fractional CTO — Websites, Apps, Servers, Databases, AI, SEO & QA
Full-stack developer working across the entire stack — websites, apps, servers, databases, AI integrations, SEO, and QA. Languages & Core: writes code in JavaScript, TypeScript, Python, PHP, Go, and Rust. Architects scalable systems for large-scale projects. Frontend & Interfaces: builds websites and web applications with React and Next.js. Crafts responsive interfaces with Tailwind CSS, Radix UI and Shadcn, adds smooth animations with Framer Motion, and interactive charts with Recharts. SEO Audit & On-Page Optimization: semantic keyword research, resolving technical indexing issues, and optimizing page load speeds. Structures page architecture, meta tags, and multi-language support (i18n). Copywriting & Content Strategy: writes technical articles, drafts precise content briefs for writers, and develops content plans. QA & Testing: full-cycle testing for websites, web services, and Android apps — manual QA for UI/UX and business logic, plus automated testing with Jest, Vitest, Playwright and E2E. Backend, Cloud & Databases: complex API integrations of any scale. Builds servers with Node.js (Express, Fastify). Works with PostgreSQL, MySQL and MongoDB, ORMs (Prisma, Drizzle), and cloud infrastructure (Supabase, Firebase, Cloudflare). Browser Extensions & Automation: develops Manifest V3 browser extensions for Chrome, Edge, Firefox and other browsers. Builds web scrapers for complex data extraction using Puppeteer and Playwright. AI & Intelligent Agents: builds custom AI agents and integrates LLMs from OpenAI, Google Gemini, and Anthropic Claude via API, including Claude Code setups. Servers & DevOps: Linux (Ubuntu) and VPS administration — setup, updates, real-time monitoring, secure process isolation, Nginx, PM2, and CI/CD deployment via GitHub Actions. Telegram Bots: develops advanced Telegram bots (Telegraf, Grammy) integrated with AI, payment gateways, Google Sheets, and crypto exchanges. Desktop Applications: builds cross-platform software for Windows and macOS using Electron and Rust. Additional expertise: site development and customization with WordPress and Astro.
AI & Distributed Systems Architect | Enterprise AI, RAG, Cloud, Blockchain | Advisory & Fractional Leadership
AI and distributed systems architect providing advisory and fractional leadership on enterprise AI, RAG pipelines, cloud architecture and blockchain-backed data systems.
Khmelnytskyi, Ukraine
Senior Backend Engineer | AI Engineering | PHP, Python, LLM Applications
Senior backend engineer working across PHP and Python, with a growing focus on AI engineering: building LLM-powered application features on top of existing backend systems and APIs.
Senior Frontend Engineer · React · Next.js · Angular | Open to new opportunities
Senior frontend engineer with deep experience across React, Next.js and Angular, building enterprise dashboards and complex UI systems. Strong focus on performance, component architecture and design-to-code fidelity.
Payment processing directly impacts company revenue, customer churn, and financial compliance. Traditional digital agencies charge $150 to $240 per hour for payment integrations, inserting non-technical coordinators between you and the engineer handling credit card tokens and webhook transactions.
ProofDevs connects you directly with independent senior Stripe developers who understand the Stripe API, write idempotent webhook listeners, and implement compliant checkout flows at transparent rates between $50 and $100 per hour.
| Implementation Factor | Software Development Agency | ProofDevs Independent Senior |
|---|---|---|
| Hourly Billing Rate | $150 – $240 / hr | $50 – $100 / hr |
| Webhook Reliability | Often lack idempotency checks, causing duplicate charges | Guaranteed webhook idempotency with Redis / DB stores |
| SCA / 3D Secure Compliance | Basic checkout redirects | Full Stripe Payment Intents with SCA & 3D Secure 2 |
| Direct Communication | Filtered through account executives | Direct technical collaboration with the engineer |
| Code Ownership | Proprietary agency scaffolding | 100% client-owned code and private Git commits |
Integrating Stripe requires handling asynchronous state transitions. A credit card payment is not guaranteed when the user submits a form; it must undergo 3D Secure authentication and bank verification via the Payment Intents API.
Senior Stripe developers architect idempotent webhook listeners that handle events like `payment_intent.succeeded` and `customer.subscription.deleted`. They store incoming `event.id` values to prevent processing the same transaction twice during network retries.
Furthermore, specialists configure automated invoice retries (Smart Retries) and customer billing portals, reducing involuntary churn caused by expired cards.
For marketplaces and platforms, senior engineers architect Stripe Connect implementations (Custom, Express, or Standard accounts), managing destination charges, application fees, and KYC verification.
Architecture Rule: The Webhook Race Condition
Redirecting users to a success page immediately after client-side payment confirmation without waiting for verified webhook events leads to fulfillment errors if network drops occur. Senior Stripe developers fulfill orders exclusively upon verified server-side webhook signatures.
Project timelines for standard commercial Stripe integration tasks.
Independent Stripe engineers charge between $50 and $100 per hour. Development is performed strictly using Stripe test mode API keys and sandbox accounts. Clients retain 100% intellectual property ownership of all custom payment logic, webhook handlers, and Git repositories.
You will receive matches with available payment integration specialists within 2 to 4 hours of submitting your technical requirements.
Rates range from $50 to $100 per hour, based on expertise in Stripe Billing, webhook idempotency, and Stripe Connect marketplaces.
Yes. Our engineers inspect webhook logs, verify signature verification, and build persistent idempotency checks to guarantee reliable transaction processing.
Yes. Our specialists implement Stripe Connect (Custom, Express, and Standard) with split payments, transfers, and seller onboarding.
You can invite developers via Stripe Team Management with restricted developer permissions, ensuring sensitive bank details remain private.
