A secure, fast API platform for fintech products

Invincible Ocean builds fintech products for B2B and B2C users. Over 19 months I grew from Associate Software Developer to Software Developer, working on the backend that its client-facing products depend on.

The products needed a large and reliable API surface for clients and internal tools, access control that separated admins from users, file storage that was never publicly exposed, and response times that held up as usage grew.

1. 01

   Build the API surface

   Architected and developed 350+ public and in-house APIs, and tested them across edge cases with Postman before they reached clients.

2. 02

   Lock down access

   Engineered role-based access control with three tiers (Super Admin, Admin, User) on top of JWT authentication, plus a customisable IP whitelist so clients could restrict where calls come from.

3. 03

   Keep files private

   Moved storage to private S3 buckets. Files are served through short-lived pre-signed URLs, so nothing is publicly addressable.

4. 04

   Make it fast

   Added Redis caching in front of hot API responses and optimised MongoDB queries and indexes using Compass and Studio3T.

5. 05

   Automate operations

   Set up Jenkins CI/CD for repeatable deployments, orchestrated scheduled CronJobs, and managed the EC2 and S3 infrastructure behind it all.

Simplified view of how the pieces connect.

• 350+ · Public & in-house APIs architected
• 40% · Faster MongoDB response times
• 40% · Less downtime from CronJob orchestration
• 25% · Better server performance
• Three-tier RBAC with JWT across the platform
• Private S3 storage served only through pre-signed URLs
• Client-configurable IP whitelisting

Details are generalised to respect employer and client confidentiality. Numbers shown are the ones I can share.