You will get a Stripe/Paystack payment system with 0 duplicate charges.
Rising Talent
Rising Talent
Project details
Stop losing money to duplicate charges + race conditions.
I fix payment bugs in Node.js/Python APIs using idempotency keys, Redis locks, and Kafka Outbox pattern. You get: root cause found, code patched, load tested with 0 duplicates, and runbook docs.
I’m a backend engineer in Lagos, Nigeria [GMT+1]. That means I ship fixes while US teams sleep. Your Stripe bug reported at 5pm PST is patched before your 9am standup.
7+ years shipping fintech APIs. 100% original code. No agencies, no juniors — you work directly with me.
If your payment service charges users twice, I’ll make it stop in 5 days or you don’t pay.
I fix payment bugs in Node.js/Python APIs using idempotency keys, Redis locks, and Kafka Outbox pattern. You get: root cause found, code patched, load tested with 0 duplicates, and runbook docs.
I’m a backend engineer in Lagos, Nigeria [GMT+1]. That means I ship fixes while US teams sleep. Your Stripe bug reported at 5pm PST is patched before your 9am standup.
7+ years shipping fintech APIs. 100% original code. No agencies, no juniors — you work directly with me.
If your payment service charges users twice, I’ll make it stop in 5 days or you don’t pay.
Programming Languages
JavaScript, Python, TypeScriptCoding Expertise
Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$450
|
Standard
$850
|
Advanced
$1,400
|
|---|---|---|---|
| Delivery Time | 3 days | 5 days | 7 days |
Number of Revisions | 1 | 2 | 3 |
Number of Pages | 1 | 1 | 1 |
Design Customization | - | - | - |
Content Upload | - | - | - |
Responsive Design | - | - | - |
Source Code |
Frequently asked questions
About Rowland
Senior Backend Engineer | Payments Systems & APIs | Python / Node.js
Lagos, Nigeria - 8:20 am local time
At a CBN-regulated bank, I built the double-entry ledger processing ₦1.5B+/day with 99.99% uptime and zero discrepancies. I specialize in systems where 1 wrong transaction = regulatory fine.
**Core expertise:**
• Double-entry accounting & ledger systems
• Reconciliation + trust account management
• Event-driven architecture: Kafka, Transactional Outbox
• Idempotent, fault-tolerant processing at 5k TPS
• PostgreSQL for financial data: row-level locking, partitioning
• Go, Node.js, TypeScript, Redis, Docker, K8s, AWS
**What clients get:**
1. Zero double-spend / zero data loss guarantees
2. Systems that pass regulatory audits
3. Sub-50ms p99 latency under concurrency
4. Full observability: logs, metrics, DLQ alerts
I’ve solved the hard problems: distributed transactions, consistency under failure, and reconciliation at scale.
If your product touches money, ledgers, or compliance — I’m the engineer you hire before it breaks.
Steps for completing your project
After purchasing the project, send requirements so Rowland can start the project.
Delivery time starts when Rowland receives requirements from you.
Rowland works on your project following the steps below.
Revisions may occur after the delivery date.
Day 1: Root Cause Audit
I reproduce the duplicate charge, trace the race condition, and share a 1-page report with the exact line causing it.
Day 2-4: Code Fix + Hardening
I implement idempotency keys, webhook locking, and outbox pattern. All code pushed to your repo branch.