I build and run systems that stay correct when things fail.

A platform that takes a profile and a job description and returns a tailored, ATS-optimised resume, cover letter, proposal or outreach email in seconds.

GPT-4o with structured outputs so responses are schema-valid rather than free-form text. A multi-hundred-line prompt system with truthfulness guardrails so the model reframes real experience instead of inventing metrics or employers.

Server-side PDF rendering across five templates. A similarity engine scoring new job descriptions against prior generations and reusing relevant output instead of re-calling the model, cutting inference cost on repeats.

Credit balances with atomic rollback, added after a failed generation left a user a credit short.

Security: JWT with refresh-token rotation and reuse detection, rate limiting, bot protection, HMAC-signed single-use short-TTL download URLs.

Note: Payment gateway is on test keys and not live. Users are on free credits.

Splits income into budget categories on the 50/30/20 model or custom rules.

Double-entry ledger where every transaction writes an entry and every deletion triggers an automatic atomic reversal through transaction linkage, so balances always reconstruct from the entries beneath them.

Atomic MongoDB $inc operations for all balance updates, so data is always consistent rather than eventually consistent.

Cron-driven month-end job carrying unspent balances forward as sinking funds. Burn-rate forecasting.

Three-tier subscription with trial, expiry and a guard that soft-locks excess buckets on downgrade.

A research-only tool with a hard no-trading line: no order placement and no broker integration anywhere in the product, on purpose.

Account and email-verification flow where sign-up succeeds but login stays blocked until the address is verified, plus password change and reset for locked-out users.

Market overview that groups NGX and US stocks into performing well, worth a closer look, and underperforming, each with current price and percentage move.

Per-stock detail pages with the fundamentals that actually explain company health, and an explainability panel that shows the factors behind a score rather than just the number. Inline plain-language glossary for terms like P/E and liquidity.

A track-only portfolio that separates stocks you are watching from stocks you own elsewhere, entered by hand. No buy or sell action exists.

Favorites lists exportable as a public link that anyone can open on the web without an account, with rate limiting on link creation to keep it from becoming a scraping vector.

I am publishing every product and architecture decision as I make it. Two posts are already up: on naming a money product that is deliberately not fintech, and on scrapping the earlier screener build before writing any frontend code.

Note: Repo is public; the README has not caught up with the current local build yet.

One billing system, one Paystack integration, one ledger. Tenant isolation at the application layer through API-key-scoped tenancy over shared tables.

Append-only double-entry ledger covering both money and prepaid credit, with balanced-entry invariants enforced in code and integer minor units so rounding cannot corrupt a balance.

Persist-then-process webhook pipeline with signature verification, deduplication and mandatory provider re-verification before entitlement. Idempotency keys and a transactional outbox for at-most-once side effects under retries.

A self-managed subscription engine built from Paystack's charge-authorization primitive with custom dunning, downgrade-and-recovery and card-update flows.

A fail-open availability strategy backstopped by a daily reconciliation job that auto-corrects missed webhooks and escalates everything else. Admin dashboard for financial monitoring, forced retries, goodwill actions and audit-logged operator actions.

Process: decision register, ADRs for every one-way-door choice, data model, API contract and risk register written before implementation code.

Submit a Git URL or ZIP and get a running app at a live subdomain. A NestJS API creates the deployment record and returns immediately, then runs the pipeline async so nothing blocks on a request timeout.

AWS CodeBuild clones the repo, auto-detects the runtime and builds an image into ECR. The image is registered as an ECS Fargate task definition and run in a private subnet, with an ALB target group and listener rule created so it is reachable at deploy-<id>.shotnubsolutions.com.

Every log line streams back to the browser over Server-Sent Events, replaying persisted lines first so a reconnecting client can scroll back. Teardown runs in reverse using ARNs stored on the deployment record.

Nine Terraform modules (VPC, IAM, ECR, S3, RDS, Route53, ALB, CodeBuild, ECS) with remote state in S3 and DynamoDB locking. RDS is private-subnet-only, encrypted at rest, reachable only from the backend security group.

Design decisions: SSE over WebSockets because log streaming is one-directional. Lazy AWS SDK imports so the app boots on a laptop with no credentials. A full local simulation mode that exercises the entire API surface without AWS.