The latest articles on DEV Community by Zevs (@dzevs). https://dev.to/dzevs https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F3809021%2Fc9439207-8c3d-48b9-98c6-d3b8f654f605.gif https://dev.to/dzevs en Zevs Fri, 06 Mar 2026 04:41:27 +0000 https://dev.to/dzevs/how-i-built-a-high-performance-sms-verification-service-with-rust-and-axum-370b https://dev.to/dzevs/how-i-built-a-high-performance-sms-verification-service-with-rust-and-axum-370b <p>I built SMSCode because I was frustrated with existing SMS verification services. Overpriced, slow OTP delivery, terrible APIs, and documentation that looked like it was written in 2010.</p> <p>So I rewrote everything from scratch in Rust.</p> <h2> The Problem </h2> <p>If you've ever tried to automate SMS verification — for testing, privacy, or bulk operations — you know the pain. Most services charge $0.50+ per number, have APIs that randomly fail, and support maybe 50 countries if you're lucky.</p> <p>I needed something better.</p> <h2> The Stack </h2> <ul> <li> <strong>Backend</strong>: Rust with Axum framework</li> <li> <strong>Frontend</strong>: Astro SSR</li> <li> <strong>Database</strong>: PostgreSQL + Redis</li> <li> <strong>Infrastructure</strong>: Bare metal servers on Proxmox</li> </ul> <p>Why Rust? Performance and reliability were non-negotiable. With 100K+ active users making real-time requests, I needed something that wouldn't buckle under load.</p> <h2> Architecture Overview </h2> <p>The system follows a domain-driven design with clear separation between:</p> <ol> <li> <strong>Number inventory management</strong> — pooling numbers across multiple providers</li> <li> <strong>Order processing</strong> — idempotent requests to prevent duplicate charges</li> <li> <strong>OTP delivery</strong> — webhook support for real-time notifications</li> <li> <strong>Background workers</strong> — cleanup tasks post-verification</li> </ol> <h2> Key Technical Decisions </h2> <p><strong>Idempotent requests</strong>: Every order has a unique key to prevent duplicates even under network failures.</p> <p><strong>Live stock checks</strong>: Before a user submits an order, we verify number availability in real-time — no more "sorry, that number isn't available" after payment.</p> <p><strong>Multi-provider pooling</strong>: Numbers are sourced from multiple providers simultaneously, giving us 200+ country coverage at competitive prices starting from $0.0044/activation.</p> <h2> Results </h2> <p>SMSCode now serves 100,000+ active users across 200+ countries with support for 700+ platforms including WhatsApp, Telegram, Google, TikTok, and Facebook.</p> <p>If you're building something that needs SMS verification, check it out at <a href="https://smscode.gg" rel="noopener noreferrer">smscode.gg</a>.</p> <p>Happy to answer any questions about the Rust/Axum architecture in the comments!</p> webdev rust programming opensource