Case study · FinTech
A secure payment gateway built for scale
An enterprise-grade payment gateway with layered security and a clean integration API.
- Industry
- FinTech
- Engagement
- Product engineering + security
- Status
- Live in production
01 · Challenge
What they brought us
Building a secure and scalable payment processing system that businesses could integrate quickly. Payments demand strict correctness, auditability and defense in depth, without making the API painful to adopt.
02 · Objectives
What success looked like
- Make integration fast for businesses
- Defense in depth through the whole transaction path
- Auditability on every transaction
- Hold up under production load
03 · Solution
What we built
Developed an enterprise-grade payment gateway with layered security, fraud controls and a clean integration API, designed so integrators get safe defaults out of the box.
Engineering
- Idempotent, versioned payment API with safe defaults
- Clear error semantics and predictable webhooks
- Careful transaction design on PostgreSQL and Redis
Security
- Threat model before the first endpoint was written
- Encryption in transit and at rest, key isolation
- Rate limiting, audit logging and fraud checks in the transaction path
Reliability
- Load-tested transaction path
- Hot spots profiled and tuned before launch
04 · Process
How we worked
Threat modeling first
Started from the attacker's view: mapped the trust boundaries, abuse cases and failure modes before writing the first endpoint.
API design
Designed an idempotent, versioned payment API with safe defaults, clear error semantics and predictable webhooks.
Security controls
Implemented layered controls: encryption in transit and at rest, key isolation, rate limiting, audit logging and fraud checks in the transaction path.
Scale and reliability
Built on PostgreSQL and Redis with careful transaction design, then load-tested the transaction path and tuned the hot spots.
05 · Stack
Built with
Backend
Database
Infrastructure
06 · Results
What it achieved
Safe defaults out of the box for integrators
Layered security controls in the transaction path
Full audit trail on every transaction
Load-tested before production release
07 · Impact
Why it matters
Payments are a trust business: one breach or one lost transaction can end a platform. AuxVault now has an API integrators adopt quickly and a security posture it can show enterprise customers, which is what turns a payment gateway from a feature into a business.
Services used
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