Ezekiel Apetu · Lagos, Nigeria (Remote)

Senior full-stack
developer.
AI SaaS, payments and billing.

Senior full-stack developer with approximately six years of professional experience, the last three spent building and operating production SaaS products that take real money. I have designed and run the systems an AI product depends on before it can charge customers: payment webhooks that credit exactly once, wallet and credit ledgers that stay correct under concurrent requests, upload validation that rejects bad files before anything is charged, and admin tooling that makes every transaction and failure easy to check.

I work in Next.js, React, TypeScript and PostgreSQL daily, integrate LLM and image AI behind quotas and kill switches, and bring product sense and marketing output alongside the code.

Next.jsReactTypeScriptPostgreSQLPrismaRedisStripePaystackAnthropic APIVercel

See the portfolio GitHub

How I work

The systems an AI product needs before it can charge customers.

Money paths

Every money path is idempotent and auditable.

Signed webhooks with idempotency keys, ledgers that run inside database transactions, reconciliation jobs with admin alerting, and per-transaction audit views.

AI with control

LLM and image AI behind quotas and kill switches.

Selfie search, transcription, note generation and semantic memory shipped to paying users, each behind one gated entry point with daily quotas and an admin off switch.

Verification

No check is trusted until it has been seen to fail.

Integration and end-to-end tests run against a real Postgres with Vitest and Playwright, backed by ESLint guard rules and per-project decision and incident logs.

Products built and operated