Backend & Infrastructure — Harbor Software Blog

Redis Beyond Caching: Queues, Pub/Sub, and Rate Limiting

Redis is one of the most misunderstood tools in the modern software stack. Most teams discover it as a cache — a faster alternative to hitting the database for frequently accessed data. They install it, configure a TTL, and move on. That is a valid

Competitive Intelligence Systems: Architecture and Implementation

Every business monitors competitors. The question is whether they do it systematically or haphazardly. Most companies fall into the haphazard camp: someone checks a competitor’s website occasionally, a sales rep mentions a competitor’s new pricing in a Slack channel, a product manager bookmarks a competitor’s

Database Migrations in Production: A Zero-Downtime Approach

It’s 3 PM on a Tuesday. Your migration is halfway through altering a 200-million-row table. The application is throwing 500 errors. Your CEO just messaged the engineering Slack channel with a screenshot of a blank page. The database is locked. You can’t roll back because

Stripe Integration Patterns for Subscription SaaS

Why Stripe Integration Is Harder Than It Looks Every SaaS founder hits the same wall. You sign up for Stripe, drop in Checkout, and think billing is solved. Three months later you’re debugging webhook race conditions at 2 AM while a customer’s subscription is stuck

Building Multi-Tenant SaaS Applications with PostgreSQL Row-Level Security

Why Multi-Tenancy Is an Architecture Decision, Not a Feature Multi-tenancy sounds simple: multiple customers share one application. In practice, it’s one of the most consequential architecture decisions you’ll make for a SaaS product. Get it right, and you scale efficiently with strong isolation guarantees. Get

Zero-Trust Security Architecture for SaaS Products

The traditional security model is a castle: hard perimeter, soft interior. Firewalls and VPNs guard the boundary, and once you are inside, you are trusted to access anything. This model was already fragile before the cloud; now it is indefensible. When your application runs across

API Design Patterns That Scale

Every API starts simple. A handful of endpoints, a few hundred requests per day, one or two client applications. Then it grows. New consumers appear — a mobile app, a partner integration, an internal analytics dashboard. Request volume goes from hundreds to hundreds of thousands.

Kubernetes in Production: What They Don’t Tell You

Every Kubernetes tutorial ends at the same place: you have a deployment, a service, and an ingress. Your application is running. kubectl get pods shows healthy green status. The tutorial declares success and moves on. What the tutorial does not cover is the next twelve

Building Resilient Microservices with RabbitMQ

Synchronous HTTP calls between microservices are a reliability liability. When Service A calls Service B over HTTP and Service B is slow or down, Service A is also slow or down. The caller inherits the callee’s failure mode. Multiply this by ten services and you