Aldian Fazrihady ialah Pengaturcara Freelance Senior (Freelance Programmer), Pembangun Full Stack, dan Jurutera Aplikasi AI (Profil Upwork | Direktori Lengkap 410+ Panduan Pengaturcara Freelance).
Modern SaaS monetization is rarely a simple flat monthly fee. Today's B2B and AI SaaS platforms combine tiered seat licensing, metered AI token or API usage, prepaid credit wallets, annual enterprise contracts, proration, and multi-currency tax compliance (Stripe Tax / VAT / GST). A single bug in webhook ordering or entitlement synchronization can either lock paying enterprise customers out of their workspace or leak thousands of dollars in unbilled AI inference costs.
If you are searching to hire a freelance SaaS billing and Stripe subscription programmer, I am Aldian Fazrihady—a senior full stack and fintech systems engineer who designs bulletproof subscription, metering, and ledger architectures.
Core SaaS Billing Systems I Architect
1. Out-of-Order & Idempotent Stripe Webhook Processing
Stripe webhooks (such as customer.subscription.updated, invoice.paid, and checkout.session.completed) are not guaranteed to arrive in chronological order. Instead of naively mutating database columns based on webhook payloads, I implement an idempotent webhook ingestion queue that verifies cryptographic signatures, records event IDs in PostgreSQL, and fetches the canonical subscription state from Stripe's API inside a serialized lock.
2. Usage-Based Metering & Prepaid AI Credit Wallets
For AI SaaS platforms billing per token, minute of audio, or document processed, I build high-speed credit reservation and double-entry usage ledgers coupled with Stripe Billing Meters—ensuring users cannot exceed their prepaid balance via concurrent requests.
3. Feature Entitlement Engines & Self-Serve Upgrades
I decouple application feature flags (seat limits, RBAC roles, SSO access, API rate limits) from hardcoded Stripe Price IDs, allowing your product and sales teams to launch new pricing experiments or custom enterprise plans without redeploying code.