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Fiverr Pro
English
$
USD
I will payment integration specialist stripe, paypal, pix, webhooks
Javier R.
Level 1
About this gig
Struggling with payment integrations that just work? I specialize in production-grade payment systems for SaaS, e-commerce, and membership platforms.
As the engineer behind EngajaMaisVoce (+$1M BRL processed) and WhoIsOutlier (Stripe + AWS S3), I've implemented:
Stripe Subscriptions with HMAC webhook verification
PayPal Billing Agreements + cancellation sync
Brazilian gateways: PIX (Woovi/OpenPix), Boleto (PagHiper), Mercado Pago
Multi-gateway fallback logic + wallet/coins systems
Server-to-Server tracking for Meta CAPI (CRO-optimized)
What you get:
Secure, idempotent webhook handlers
Subscription logic (trials, coupons, proration)
Error handling + retry mechanisms
Admin panel for payment monitoring
Full source code + runbook
No more lost payments, chargebacks, or broken checkout flows. Let's make your monetization bulletproof.
Message me first to confirm your gateway and scope.
Get to know Javier R.
Javier R.
Tech Lead Fullstack Engineer
Level 1
- FromArgentina
- Member sinceDec 2022
- Avg. response time1 hour
- Last delivery3 days
Languages
Spanish, English
I am a self-taught programmer passionate about continuous learning. I have strong skills in JavaScript, Nodejs, React js, MongoDB, MySQL, HTML, CSS, Tailwind CSS, and I have worked with a variety of frameworks such as Express, SocketIO, and WebSocket. I have experience in IoT projects developed with Nodejs, React, Arduino, and WebSockets, showcasing skills in software, hardware, and teamwork. I have excelled in programming competitions and am excited to work on challenging, high-quality projects.
https://javier-rodriguez-portfolio.pages.dev/
