1. Monolithic Core, Microservice Muscles
Although it is tempting to divide everything into microservices when first starting the project, this is falling into the error of "Over-engineering". At DoWaba, we adopted the Majestic Monolith approach.
Core business rules, database management, and API services run on a powerful and rock-solid Laravel core. However, we separated the parts requiring very high concurrency, such as real-time audio processing, WebSockets, and heavy AI proxy operations, into small Node.js-based microservices. While our voice bridge processes hundreds of audios per second, it never tires our main database.
2. Queue Architecture: "Never Do It Instantly, Put It in the Queue"
No heavy process occurring in the system (sending a bulk email to a customer, downloading media from WhatsApp, or sending a prompt to the AI) is done synchronously while the user is waiting.
Everything is sent to Redis or RabbitMQ queues. Dozens of Workers running in the background melt these queues. Thanks to this, even if 1 million messages arrive in a day, the system does not crash; the queue just gets longer, and we melt the queue rapidly by spinning up new Worker servers.
3. Multi-Tenancy Database Strategy
Keeping the data of thousands of different companies (tenants) in the same system poses great risks. Company A's messages should never accidentally fall onto Company B's screen.
In DoWaba, each company's data is logically isolated (Tenant ID based). While queries are being made, the core structure of the system automatically adds the WHERE site_id = X rule to each query. Even if the developer wants to, they cannot fetch the data of another company (Global Scope Isolation). In critical projects (Large hospitals, banks), we provide maximum security by completely separating the database schema (Separate Schema).
4. Auto-Scaling in Seconds
When a big brand's Black Friday campaign starts on Friday, traffic suddenly increases 10-fold. The Load Balancer immediately monitors CPU usage. As traffic increases, clone servers boot up in our cloud infrastructure within 10 seconds, meet the traffic, and when the campaign ends and night falls, the servers shut themselves down again to save costs.
Here is the secret to managing millions of users uninterruptedly: using queues in the right place, isolating data strictly, and the freedom to add horizontal servers when necessary.