AI products, from idea to live revenue
I'm Devin — a solo full-stack engineer who ships complete AI products end to end: architecture, build, deploy, payments. Not hours of dev time — outcomes that charge credit cards.
8+ years full-stack · Next.js / Go / React Native · LLM apps & agents · bilingual English/中文 delivery
What I deliver
One accountable engineer for the whole loop — including the parts that usually get hand-waved.
Full-cycle AI product
SaaS or app taken from zero to live with real payments: auth, billing, credits, admin, deploy. Don't see your product yet? That's the point — I build to order.
Architecture & full-stack build
Frontend/backend architecture, development, deployment and operations. LLM integration, RAG, agents, multi-tenant billing systems.
AI integrations & chatbots
Chatbot and AI-feature integration into existing products, automation workflows, document pipelines. Scoped, fixed price, no surprises.
Differentiators: bilingual EN/中文 delivery · China-entry advisory (sourcing, remote teams, market navigation for Western clients) · I run my own live product matrix, so deployment/billing isn't theory
Proof, not promises
Everything below is real and mine. The flagship is live — go kick its tires.
PlotiVa — AI SaaS, zero → paid product
LiveAI long-form fiction studio: story bible, world graph, continuity review. Next.js + Go + credits billing + Stripe/PayPal checkout — idea to live revenue in 2 months.
plotiva.whataicando.site ↗PLANET — cross-platform app + backend
Multi-user pet-care app: Expo/React Native on three platforms + Go/PostgreSQL backend. 68/68 E2E tests passing, submitted to the App Store.
bidagent — vertical AI agent
AI proposal-drafting automation for government contracting, built on industry-specific research.
saas-core — multi-tenant platform base
Shared auth, billing and subscription infrastructure powering a 30+ site product matrix (whataicando.site).
How it goes
Scope call (30 min)
We nail down what "done" means, what it costs, and what's deliberately out of scope. Fixed price or hourly, decided here.
Weekly demos
You see a running build every week — not a status report, the actual product. Course-correct before things harden.
Live, with receipts
Deployed, documented, payments wired. You own everything — repo, infra, accounts. Handover screencast included.
Start a conversation
Tell me what you're trying to build or fix. I reply within 24 hours, usually with questions that mean I read it.
Also on Upwork (Devin J., Full-Stack AI SaaS Dev) · Timezone-flexible across US & EU hours · 中文沟通同样欢迎