Adonis Xiao

Built Exeltiq, a production CRM SaaS platform, as the primary full-stack developer in a small team working directly with founders. Owned architecture and implementation across frontend, backend, authentication, data modeling, and deployment. Implemented APIs with FastAPI and PostgreSQL schemas for core SaaS operations, and integrated Clerk for authentication and user management. Delivered a component-driven React frontend with attention to performance and maintainability, and applied WCAG accessibility standards across key UI components. Implemented Playwright/Cypress test suites and set up GitHub Actions CI/CD to run tests on every pull request. Added Sentry-based telemetry and used it to investigate and fix production incidents, improving reliability and iterating on UX with founder and early-user feedback.

Built Exeltiq, a production multi-tenant CRM for gyms, clinics, and sports clubs in Cyprus. Designed multi-tenant architecture and implemented Clerk JWT authentication for business owners and members. Implemented Stripe billing for subscriptions and productized add-ons such as SMS credits, booking packages, and shop checkout. Built an appointment booking flow where members buy packages and redeem them for fitness, physio, and grooming services. Developed an SMS credit wallet (Stripe to credits to Twilio) and automated SMS/email campaigns. Implemented a referral program with discounted first-month subscriptions and non-refundable platform credits.

Integrated AI capabilities into user-facing product experiences, focusing on practical usability, reliability, and business value. Explored AI-driven automation patterns to improve user productivity within existing product surfaces, and applied full-stack engineering skills to ship AI-powered features with appropriate human verification for correctness and security.