I fix, upgrade and rebuild the backend your business runs on.
I'm Pablo, a senior backend engineer. Payments that fail or need to be added, or a legacy system nobody dares to touch anymore — I take it end to end, without stopping your business. Clear scope, written proposal, working in your timezone.
What I can do for you
Payments
Add payments to your site or app
One-time payments and saved cards with Stripe, PayPal, Square or Authorize.net, plus Apple Pay and Google Pay. Webhooks, receipts and refunds done right from day one.
Fix a broken or declining checkout
Payments failing, legitimate cards getting declined, duplicate charges, webhooks that never arrive, 3DS / SCA challenges that kill conversion. I find the cause and fix it.
Subscriptions & recurring billing
Plans, trials, renewals, upgrades and downgrades, failed-payment retries and a customer billing portal — so recurring revenue actually recurs.
Switch or add a payment provider
Move to a better gateway or add a second one without downtime, keeping saved cards where the providers support it.
Legacy systems
Upgrade an outdated stack
Old PHP or Laravel versions without security patches, dependencies that can no longer be updated, a server nobody wants to touch. I bring it to a supported, maintainable version.
Rebuild without stopping the business
A new system built in parallel with the old one, same behavior verified module by module, proven business logic reused — and a carefully planned cutover that minimizes disruption for your customers.
Replace an outdated mobile app
Apps on Cordova or other declining technology rebuilt with React Native, sharing the same backend and data.
Cloud, CI/CD and observability
Files off the server disk and into S3, automated deploys, audit logs and error tracking — so problems show up before your customers report them.
Problems I've already solved
Legacy SaaS at full parity in 5 weeks, not 3 months
A Laravel 5.7 system without security patches for years, 111 tables and a Cordova app. I rebuilt it on a modern TypeScript stack in parallel with the live system: 419 endpoints and 37/37 reports at full parity, plus a new mobile app — and found a bug that was under-reporting accident metrics 20×.
Card approval rate from ~50% back to ~91%
Approvals in Japan and Europe had collapsed. I implemented 3DS2 correctly, enriched the data sent to card issuers and fixed recurring-payment flags. Hundreds of thousands of dollars in legitimate sales stopped being declined.
PHP 5.6 → PHP 8, checkout ~50% faster
Migrated a legacy codebase to PHP 8 + Laravel 9 and replaced manual deploys with CI/CD. Landing and checkout load times dropped by about half.
10+ payment providers in one checkout
Cards, Apple Pay, Google Pay, buy-now-pay-later, bank payments and local methods across North America, Europe and Asia, unified behind a single payment layer.
How it works
Tell me what is going on
Two minutes with the form below. No sales pitch.
Short call
A free 20-minute call to understand your setup and goals.
Written proposal in 48h
Scope, price and timeline in writing. For larger or undocumented systems, a short paid diagnostic comes first.
Build, test, go live
Tested before anything reaches your customers, then launched, with a short handoff doc.
What you get
- A senior engineer, directly — no agency layers or account managers.
- Clear written English, async-friendly, 1–2 hours ahead of US Eastern.
- Your business keeps running: changes ship in parallel or behind carefully planned cutovers.
- Card data never touches your server: I use provider-hosted fields and checkouts to keep your PCI scope minimal.
- The code and the accounts are yours from day one.
FAQ
What platforms do you work with?
Custom-built websites, apps and APIs — mainly PHP / Laravel and Node.js / TypeScript, with MySQL, PostgreSQL or MongoDB. If you are on a hosted builder like Shopify, Wix or Squarespace, their built-in payments are usually the right answer and you probably do not need me.
My system is old and undocumented. Is that a problem?
No — that is the usual starting point. I read the existing code and database, document what it really does, and keep that behavior while the stack changes.
How much does it cost?
After the call you get a written proposal with scope and price. Well-defined work gets a fixed price; larger or undocumented systems start with a short paid diagnostic so the estimate is real. Most payment integrations take days, not months; rebuilds are scoped in phases so you see progress early.
How do contracts and payment work?
Written scope, invoice in USD, a deposit to start and the rest on delivery. Happy to sign an NDA.
What size of projects do you take?
Well-scoped projects with part-time dedication: an integration, a fix, an upgrade, or a rebuild split into phases. I am not available as a full-time contractor or to join a team indefinitely.
Are you available right now?
I take a limited number of projects at a time, so I can give each one proper attention. Send the form and I will tell you honestly when I can start.
Tell me about your project
I reply within one business day.