Senior Full-Stack Ruby on Rails Developer

Hellotext is the next-generation AI platform for eCommerce growth. Brands use Hellotext to power AI Playbooks that recover carts, re-engage customers, automate support, and send highly personalized WhatsApp/SMS campaigns. We re growing fast and we need a Senior Rails Engineer who can own complex integrations, scale our systems, and ship features that directly impact tens of millions of messages every month. If you love: • Rails architecture • Hotwire/Turbo/Stimulus • High-volume integrations • Scaling data pipelines & jobs • Building product, not ticket factories …then you will love this role. What You ll Do As a Senior Full-Stack Ruby on Rails Developer you will: 1. Own integrations end-to-end You ll build and maintain the APIs and webhooks that power our automation engine: • Shopify, Woocommerce, Tiendanube, VTEX, Magento, Salesforce. • ERPs Integrations • MercadoLibre customers & orders • Meta (WhatsApp), AppsFlyer, attribution partners • Payment and billing integrations • Event ingestion for abandoned carts, purchases, inventory, returns, etc. 2. Build and scale core product features You ll work closely with Founder + Product to deliver new features 3. Build clean, reactive UI with Hotwire No React. No SPAs. Pure Rails with: • Turbo Streams • Stimulus controllers • Tailwind CSS • Real-time updates (Inbox, Playbook stats) • Seamless multi-step wizards⠀ 4. Architect for performance and scalability You ll improve and scale the systems behind: • High-throughput message delivery (WhatsApp/SMS/IG/WA Cloud API) • Async processing (Sidekiq queues, concurrency tuning) • Webhooks ingestion at high volume • Caching strategies (Redis, DB read optimizations) • Reliable background processing & backpressure control • Database performance: indexing, partitioning strategies, slow query reductions • Horizontal scaling via Kamal + containers 5. Work side-by-side with our AI team You don t need to be an “AI engineer” but you ll help wire the backend so these systems run flawlessly. What Makes This Role Special • You ship features deeply used by big LATAM retailers and thousands of merchants • You will shape the foundation of the entire platform • You work directly with the founder, not layers of management • You never get bored — every week new integrations, new playbooks, new UX • You join a tiny team with massive leverage • You get to work with one of the most advanced AI architectures in eCommerce This is not a corporate Rails job, this is the kind of role where your code is powering millions of messages, automations, and purchases every single day. Our Tech Stack Ruby on Rails, Hotwire (Turbo + Stimulus), Tailwind CSS, PostgreSQL, Redis, Sidekiq, Kamal (deployments), AWS & Hetzner, OpenAI. Who You Are You are a senior generalist who cares about shipping great products and solving real problems. Core • 4+ years of Ruby on Rails • Deep experience with API integrations and event-driven systems • Strong Hotwire/Turbo/Stimulus skills • Comfortable building product end-to-end • Superb debugging skills • Sidekiq mastery (queues, retries, concurrency, backpressure) • Experience maintaining systems that require high uptime⠀ Scaling Experience (Required) • You ve scaled Rails apps under high load • Designed & optimized background job pipelines • Handled webhook storms, retries, and burst traffic • Improved database performance (indexes, slow queries, partitioning) • Tuned Redis caching layers • Built or maintained multi-node environments • Familiar with rate limiting, idempotency, and reliability patterns • Understand messaging system bottlenecks (WhatsApp/SMS throughput, fan-out jobs) ⠀ Nice-to-haves • Experience with Shopify/VTEX • Understanding of LLM-based systems or AI agents • Familiarity with APM tools (New Relic, AppSignal, Datadog) • Interest in product design and merchant experience Location Latin America preferred (Uruguay, Colombia, Ecuador, Argentina, Brazil, Mexico, Peru). But we hire globally for the right candidate.