Portfolio Projects That Prove You Can Handle Money
5 portfolio projects: 1) E-commerce checkout with Paystack and idempotent webhook handler. 2) Subscription billing system with failed payment retry. 3) Marketplace with Paystack subaccount split payments and vendor payout dashboard. 4) M-Pesa + Paystack dual checkout with channel routing. 5) Bulk payout system with dual-approval workflow. Document each with security choices, test coverage, and architecture diagram.
Project 1: E-Commerce Checkout with Idempotent Webhook Handler
Build: A product listing page → Paystack checkout → order confirmation. Webhook handler that fulfills orders on charge.success with idempotency check (never fulfill twice for the same reference).
What it signals: You understand the full payment cycle, not just the frontend checkout. You handle duplicate webhook delivery. You write tests for the webhook logic.
Document: "Webhooks validated with HMAC-SHA512. References stored in DB before fulfillment — duplicate webhooks return 200 without re-fulfilling. Test coverage: 92% for webhook handler."
Project 2: Subscription Billing with Dunning
Build: Paystack Plans + subscriptions + invoice.payment_failed webhook handler. On failed payment: retry logic (3 attempts at 3-day intervals), email notification to subscriber, graceful account downgrade after exhausted retries.
What it signals: You understand subscription lifecycle, not just one-time payments. You handle the unhappy path. You think about business impact (when to cancel vs. retry).
Document: "Subscription state machine: active → past_due → cancelled. Retry logic: 3 attempts at T+0, T+3, T+6 days. Customer email on each failure. Failed payments logged with gateway_response for analysis."
Project 3: Marketplace with Subaccount Split Payments
Build: A two-sided marketplace (e.g., tutors and students). Vendor onboarding creates a Paystack subaccount. Student payment splits between platform and tutor at checkout. Vendor payout dashboard shows balance and transfer history.
What it signals: You understand multi-party payment flows, subaccount management, and split payment configuration. This is a senior-level portfolio project.
Project 4: M-Pesa + Paystack Dual Checkout (Kenya)
Build: A checkout page that detects the customer's location (or lets them choose) and shows M-Pesa STK push for Kenyan customers, Paystack card checkout for others. Both payment paths write to the same orders database and trigger the same fulfillment logic.
What it signals: You understand the African payment landscape, mobile money, and how to build for multiple payment providers without duplicating fulfillment logic.
Start Building
See building a payments portfolio for how to present these projects effectively.
Key Takeaways
- ✓A basic checkout with idempotent webhook handling proves more than 10 API tutorial projects.
- ✓Include a subscription system with dunning — failure path handling is what hiring managers want to see.
- ✓A marketplace with split payments is the highest-signal portfolio project for senior roles.
- ✓M-Pesa + Paystack dual checkout shows East Africa market knowledge.
- ✓Document security decisions in your README — they reveal your understanding of payment risk.
Frequently Asked Questions
- How do I deploy a portfolio payment project without spending money on a server?
- Use free tiers: Vercel (Next.js frontend + API routes), Railway or Render (Node.js/Python backend, free tier), Neon or Supabase (PostgreSQL, free tier). Keep the Paystack integration in test mode — no real money moves. Ngrok or Cloudflare Tunnel for local webhook development if you need to test webhooks before deploying.
- Should I include real payment data in my portfolio demo?
- Never. Always use Paystack test mode. Test card 4084084084084081 (CVV 408, any future expiry) triggers a successful payment in test mode. Your portfolio demo should be completely functional using Paystack test keys. Hiring managers and clients can test the flow themselves without any real money.
- What stack should I use for portfolio payment projects?
- Use whatever you know best, but Node.js (Express or Next.js API routes) is the most common for Paystack integrations and easiest for reviewers to understand. Python (Django or FastAPI) is a good second choice. The stack matters less than demonstrating payment-specific skills: idempotency, webhook security, test coverage.
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