Full Stack Engineer (React/Node.js)

**About Pyyne** Pyyne is a modern technology consultancy engineering the next generation of digital products and services. At Pyyne, we believe in using technology to unlock business potential, create sustainable growth, and drive forward digital excellence. Our solutions range from advanced Software Engineering, Cloud, and Data \& AI solutions. **About The Role** Our client is an AI\-powered growth intelligence platform for DTC brands, aggregating data from Meta, Google Ads, Shopify, TikTok, and Klaviyo with Claude AI layered on top for analysis and content generation. The platform was built by a non\-technical founder using AI\-assisted tools and is not yet production\-ready. This engagement is focused on turning it into a properly functioning, production\-grade SaaS product with a real path to market. The current codebase has meaningful functionality but requires a disciplined engineering hand to harden, complete, and scale. We’ve done the due diligence, reviewed the code, and begun making the appropriate changes, now we need a full time dev to come in and own the product. You'll be the sole engineer on this project, working directly with product stakeholders. You'll own the full technical roadmap and execution. A discovery phase is currently underway. The new engineer on this project will receive a technical handoff and prioritized backlog before work begins. **Key Responsibilities** Security * Remediate plaintext storage of OAuth tokens and API keys in the database * Enforce proper route\-level authorization — currently authenticated users can access and mutate resources belonging to other clients * Implement input validation across all API routes Compliance * Broken unsubscribe links in all outgoing emails (CAN\-SPAM) * Fabricated data displayed to users without disclosure (simulated order feed, randomized revenue predictions) Integrations * Complete and stabilize connections to Meta, Google Ads, TikTok, Shopify, and Klaviyo * Implement the Google Ads token refresh flow (refresh token is stored but never used) * Wire up the Shopify webhook handler (written but not connected) * Resolve Meta API version inconsistencies across the codebase * Add rate limit handling to sync functions Infrastructure * Set up error monitoring * Establish a CI/CD pipeline and staging environment * Introduce test coverage for critical paths * Migrate schema management from prisma.db push to a proper migration history **Must Have Skills:** * 5\+ years of full\-stack engineering experience * Strong TypeScript and Next.js (App Router) * PostgreSQL and Prisma ORM * Experience inheriting, auditing, and refactoring existing codebases * Experience with LLM API integrations in production, including cost management and rate limiting * Familiarity with multi\-tenant SaaS architecture * Comfortable owning a project solo and communicating directly with a non\-technical stakeholder **Nice To Have Skills:** * Experience with any of the following Integrations: Meta Graph API, Google Ads API, Shopify Admin API, TikTok Ads API, Klaviyo API **Benefits:** * Flexible remote working environment. * Career development opportunities in a fast\-growing company.