Scaling Next.js for High-Concurrency FinTech Apps
Lessons learned from building a tax compliance platform handling millions of requests.
High concurrency in FinTech isn't just about handling traffic; it's about maintaining data integrity and transactional consistency under load.
Database Locking Strategies
When dealing with financial ledgers, optimistic locking often fails under high contention. We found that a hybrid approach, utilizing Redis for distributed locking on "hot" accounts while relying on Postgres row-level locking for final settlement, provided the best balance of performance and safety.
Edge Caching vs. Freshness
Next.js offers powerful caching mechanisms, but in FinTech, stale data is a liability. We implemented a granular revalidation strategy using surrogate keys to ensure that users always see their up-to-the-second balance without overloading the origin server.