Senior Fullstack Developer (Multi-Tenant SaaS Migration) - Part-time - LATAM/NA

Full-Stack Engineer — SWAGO / MerchOS

About us

SWAGO is a family-owned custom apparel and promotional products company operating out of Miami since 1986. We design, embroider, and print custom hats, shirts, polos, hoodies, and branded merch for businesses across the country — restaurants, contractors, sports teams, schools, corporate clients.

For the last year, we've been quietly building MerchOS.io — a SaaS platform that turns our 40 years of merch-production know-how into a product. The goal is to let any brand, agency, or company spin up its own branded merch storefront, manage orders, handle artwork approvals, and run campaigns without ever needing to talk to a sales rep. SWAGO's own e-commerce site is the flagship tenant; the rest of the platform is being built around it.

What you'd be working on

The Role We're looking for an experienced full-stack engineer to take the platform from its current single-tenant architecture to multi-tenant, enabling multiple brands to operate on their own subdomains with independent branding, catalogs, and admin teams.This is a 2-3 month engagement at 20-40 hours per week, working closely with the founder. We're at the "make it real" phase — less greenfield design, more careful, surgical work to get to a launchable v1.

What You'll Be Doing

• Architect and implement multi-tenant infrastructure (tenant isolation, subdomain routing, data segregation)
• Migrate the existing single-tenant system to support multiple tenants
• Build tenant onboarding flows and admin management features
• Refine and clean up existing codebase as needed
• Work independently with weekly check-ins and code reviews

Requirements

Must-Have:

• Strong experience with multi-tenant architecture (tenant isolation, subdomain routing, data partitioning)
• Expertise in React, TypeScript, Node.js
• Experience with Supabase or similar backend-as-a-service platforms
• Comfortable working full-stack (70% backend, 30% frontend)
• Strong communication skills in English
• Ability to work independently and take ownership

Nice-to-Have:

• Experience with React Router v7 or similar SSR frameworks
• Familiarity with Stripe integrations
• Experience with e-commerce or SaaS platforms

Stack

• Frontend: React 18, TypeScript, React Router v7 (framework mode / SSR), Tailwind CSS, Radix UI, TanStack Query, Vite + SWC
• Backend: Supabase (Postgres + Auth + Storage + Deno Edge Functions)
• Payments: Stripe
• Design tooling: Fabric.js for the in-browser product designer
• Hosting: Vercel