Staff Augmentation in Amsterdam, Netherlands

Fintech / Payments

An Amsterdam-based payment platform serving 3,200 European merchants was experiencing rapid growth — transaction volume had tripled in 12 months — and the engineering team (22 developers) could not keep pace. Three critical needs: (1) The platform needed to add 6 new European payment methods (Bancontact for Belgium, Przelewy24 for Poland, Multibanco for Portugal, Trustly for Nordic countries, EPS for Austria, and giropay for Germany) to serve merchants expanding across Europe — deadline: 14 weeks for the first 3, 22 weeks for all 6. (2) The infrastructure needed to scale from 500 TPS (transactions per second) to 2,000 TPS to handle Black Friday and holiday traffic without degradation. (3) PCI-DSS Level 1 recertification was due in 18 weeks, requiring: penetration testing remediation, access control documentation, and network segmentation verification. The CTO needed: 4 senior backend developers (Go — the platform's primary language for payment processing services), 2 senior DevOps engineers (AWS/Kubernetes — infrastructure scaling and PCI-DSS compliance), and 1 senior QA engineer (payment testing across 6 European payment methods with country-specific test environments). Total: 7 engineers. The company had been trying to hire for 3 months — 2 positions filled, 5 still open. Amsterdam's developer market was too competitive to fill the remaining positions before the deadlines.

We assembled the 7-person team in 10 days: (1) Team composition: 4 senior Go developers — 2 with payment processing experience (understanding of payment lifecycle: authorization, capture, refund, chargeback), 1 with European payment method integration experience (SEPA, iDEAL — transferable knowledge to the 6 new payment methods), and 1 with high-performance Go systems experience (optimizing for the 2,000 TPS throughput target). All four understood PCI-DSS scope implications — writing code that processes cardholder data requires specific handling practices. 2 senior AWS/Kubernetes DevOps engineers — experience with: auto-scaling payment infrastructure (handling 4x traffic spikes during peak periods), PCI-DSS compliant cloud architecture (network segmentation, encryption, access logging), and infrastructure-as-code (Terraform) for reproducible, auditable deployments. 1 senior QA engineer — experience with payment testing including: test transaction flows for multiple payment methods, sandbox environment configuration for European payment providers, and regression testing for payment processing (ensuring new payment methods don't affect existing ones). (2) Integration (first week): PCI-DSS awareness briefing (all developers understood: cardholder data handling rules, network segmentation requirements, and logging standards). Codebase orientation with existing tech leads (Go microservices architecture, payment processing flow, and deployment pipeline). Payment provider onboarding (sandbox credentials for the 6 new payment providers — testing could begin immediately). (3) Execution: Payment method integration (weeks 1-22): each payment method followed a standardized integration pattern — provider API integration, transaction lifecycle implementation (authorize/capture/refund/void), webhook handling for asynchronous payment notifications, error handling and retry logic, and merchant dashboard display. The first 3 methods (Bancontact, Przelewy24, Multibanco) delivered in 12 weeks (2 weeks ahead of deadline). All 6 methods delivered in 20 weeks (2 weeks ahead). Infrastructure scaling (weeks 1-16): Kubernetes horizontal pod autoscaling configured and load-tested to 2,500 TPS (25% above the 2,000 TPS target for safety margin). Database connection pooling optimized. Redis caching layer implemented for merchant configuration data. CDN configuration for static assets. Load testing with realistic traffic patterns simulating Black Friday scenarios. PCI-DSS preparation (weeks 1-18): penetration test findings remediated (12 medium-severity and 3 high-severity findings from the external pen test), access control documentation updated, network segmentation diagrams produced, and security policy documentation reviewed and updated. (4) Knowledge transfer: structured handover to the permanent team over 2 weeks — payment method integration documentation, infrastructure runbooks, and PCI-DSS compliance documentation.

Payment method delivery: all 6 European payment methods launched ahead of schedule. Merchant adoption: 340 merchants enabled at least one new payment method within the first month. The Polish market (Przelewy24) was the biggest win — 45 Polish merchants onboarded in the first 6 weeks, representing a new market the platform had not previously served. Infrastructure scaling: platform sustained 2,200 TPS during Black Friday with zero degradation (target: 2,000 TPS). The 25% margin above target proved essential — actual Black Friday traffic peaked at 2,150 TPS, which would have caused degradation without the scaling work. Zero payment processing downtime during the holiday period. PCI-DSS recertification: passed Level 1 audit with zero critical findings (compared to 3 high-severity and 12 medium-severity findings in the previous year). The QSA (Qualified Security Assessor) specifically noted improved documentation quality. Team quality: the CTO's assessment: "The augmented developers integrated seamlessly. After the first sprint, I couldn't distinguish their work from our permanent team's output — same coding standards, same review rigor, same operational awareness." Cost: €380,000 for the 22-week engagement (7 developers). The company estimated permanent hiring cost: €70,000-€100,000 per developer annually × 7 = €490,000-€700,000 annual salary plus €35,000-€70,000 in recruitment fees — and the first 3 positions would not have been filled before the 14-week payment method deadline.