Comprehensive security assessments for fintech systems, APIs, and web applications. I find the vulnerabilities attackers exploit, before they do.
Most security breaches exploit known vulnerability patterns: authentication flaws, payment integration bugs, API misconfigurations. The fixes are often straightforward, but finding them requires systematic analysis.
Companies typically discover these issues after an incident: unauthorized transactions, data breaches, or worse. By then, you're dealing with financial losses, regulatory scrutiny, and customer trust damage.
A thorough security review before an incident costs a fraction of dealing with one after.
I got serious about security after a bug I missed cost a client nearly $10,000.
It was a webhook replay attack on a payment integration. Attackers discovered they could replay payment notifications multiple times before my system checked for duplicates. A single deposit credited the account 2, 3, sometimes 6 times. Classic race condition, and I didn't catch it until money was gone.
That failure changed how I approach code. I stopped trusting "it looks fine" and built systematic processes to catch what human eyes miss.
The redemption: I later returned to audit that same system. Found the exact vulnerability that was exploited, plus 23 more. Then performed forensic analysis on the production database — quantified $7,149 in fraudulent deposits over 42 days, identified the attackers, and located $5,110 still recoverable in wallets.
From costly mistake to complete incident response. I help teams find these issues before they become expensive lessons.
Combined results from fintech backend audits:
Across multiple fintech backends. Client details under NDA.
Every audit is tailored to your stack and risk profile. Common focus areas:
| Area | What I Check |
|---|---|
| Authentication | Session management, token handling, password policies, MFA implementation |
| Authorization | Role-based access, privilege escalation, IDOR vulnerabilities |
| Payment Integrations | Webhook security, callback validation, replay protection, race conditions |
| API Security | OWASP Top 10, input validation, rate limiting, error handling |
| Data Protection | Encryption at rest/transit, PII handling, secrets management |
| Financial Logic | Balance manipulation, double-spend, transaction integrity |
| Infrastructure | Database security, logging gaps, dependency vulnerabilities |
I combine AI-assisted systematic analysis with manual expert review. This isn't just running automated scanners; it's a structured methodology.
How it works: I use Claude AI with custom prompts tailored to your specific stack, domain, and risk areas. AI handles breadth, systematically checking every file, endpoint, and integration. I handle depth, understanding your business logic, filtering false positives, and catching contextual issues tools miss.
8 years building payment systems, wallets, and financial applications. I know where bugs hide in fintech code.
Prompts written per project based on your tech stack, integrations, and specific risk areas. Not generic templates.
SAST tools, dependency scanning, manual review, and business logic analysis. Each layer catches what others miss.
Prioritized findings with severity ratings, business impact, and code-level fix recommendations.
Real vulnerability classes found in fintech audits:
Payment webhooks accepted without idempotency checks. Attackers could replay successful payment notifications to credit accounts multiple times from a single deposit.
Concurrent withdrawal requests could bypass balance checks, allowing users to withdraw more than their available balance.
Administrative endpoints accessible to authenticated users without role verification. Any logged-in user could access admin functions.
OTPs generated using predictable seeds based on timestamp. Attackers could calculate valid OTPs for any user.
For active security incidents. Available within 24 hours.
Comprehensive security review for production systems.
Targeted review of specific areas: payment integrations, authentication, or API endpoints.
Naira pricing available for Nigerian companies. Let's discuss what works for your budget.
30 min to understand your system, risk areas, and concerns
Clear scope, timeline, and pricing based on your specific needs
Secure access to codebase and relevant documentation
Systematic review using AI-augmented analysis and manual review
Prioritized findings with severity, impact, and fix recommendations
Call to discuss findings and answer questions
I have deep experience with Node.js/NestJS, Python, and Go backends. I can review most modern stacks; we'll discuss your specific setup on the discovery call.
Automated scanners find known patterns. I find business logic flaws, race conditions, and integration vulnerabilities that tools miss. I use scanners as one input, not the whole process.
I focus on code-level security review rather than black-box pentesting. If you need network/infrastructure pentesting, I can recommend specialists.
Yes, I offer retainer arrangements for ongoing code review and security guidance. Useful for teams shipping frequently.
Yes. I offer incident response services and can start within 24 hours. Reach out immediately; every hour matters.
Whether you need a full security assessment or just want to discuss your concerns, I'm happy to talk.
I usually respond within 24 hours. For active incidents, mention "urgent" in your subject line.