Full-Stack Developer — Stripe Billing + AI-Native Development

We are looking for an experienced full-stack developer with strong Stripe experience to improve our existing subscription architecture and implement our finalized pricing and billing redesign for an existing B2B SaaS application. We want an AI-native developer who effectively uses Claude Code, OpenAI Codex, or similar tools to accelerate development, while personally reviewing, testing, and taking responsibility for all final code. About GeoIntegrate: GeoIntegrate (geo-integrate.com) is a B2B SaaS platform for geotechnical engineering workflows. We have an existing production application and are redesigning and improving its pricing, subscription, and billing system. Phase 1 — Paid Technical Test: Existing Subscription Issues We currently have two known issues: 1. Subscription renewal/access synchronization: A payment or renewal can succeed in Stripe but fail to update the local dj-stripe state correctly, resulting in incorrect application access or subscription controls. 2. Stripe customer/account synchronization: A successful payment can become associated with Stripe correctly while the corresponding application company/user does not receive the correct subscription state. The developer should investigate the actual root causes and implement a durable fix rather than only patching the symptoms. Expected reliability direction: * Keep local dj-stripe data for normal fast operation * Treat Stripe as authoritative for actual billing/subscription state * Fall back to Stripe when critical local state is missing or inconsistent * Provide reconciliation for missed/stale synchronization * Maintain reliable company/user ↔ Stripe Customer mapping * Handle webhook retries and duplicates safely The existing implementation must be reviewed first. Avoid unnecessary rewrites, and propose a better approach if appropriate. Regression tests should be added for both reported issues. Expected effort for Phase 1: approximately 4–8 hours, depending on the root cause and the level of synchronization/reconciliation work required. Continuation to Phase 2 will depend on satisfactory performance. Phase 2 — Pricing, Subscription & Billing Implementation Phase 2 will modernize and expand the existing pricing, subscription, and billing system based on the finalized designs, while improving the underlying Stripe integration and preserving existing application behavior wherever possible. Implement the supplied finalized designs and deliver a complete, tested, production-ready result. Customer Web * Basic / Standard / Professional plans * Monthly / Annual pricing and annual discount * Concurrent-user limits by plan * Discount codes with live price updates * Monthly and annual credit-card subscriptions * Saved/default payment methods and add-card checkout * Annual-only invoice option * Invoice-request and admin-approval workflow * ACH / Wire / Check and PO-number handling * Stripe-generated invoices and receipts * Billing History * Subscription activation, renewal, cancellation, and related states Admin Panel * Updated company/user management * Trial extension * Plan & Billing information * Invoice-request review and approval * Manual invoice pricing and payment terms * Billing email management * Billing History and payment records * Commercial document management for Contracts, Quotes, Purchase Orders, Amendments, and Other documents Stripe / Backend * Subscriptions, prices, discounts, payment methods, invoices, and receipts * Reliable webhook and subscription-state synchronization * Apply the reliability improvements identified in Phase 1 * Secure Stripe integration without storing raw card information in our application AI-Native Development The developer is expected to actively use Claude Code, Codex, or comparable AI coding tools for codebase investigation, implementation, testing, debugging, and review. AI-generated work must be personally reviewed, understood, tested, and validated. The developer remains responsible for correctness, security, maintainability, regression prevention, and production quality. Reasonable AI coding-tool costs can be provided or reimbursed if needed. Testing & Delivery The final implementation must be fully tested, including credit-card and invoice flows, renewals, cancellations, payment failures, discounts, payment methods, invoice approval, PO handling, and webhook edge cases. Development will initially use Stripe sandbox/test mode. Production Stripe credentials will not be shared during development. Deliverables should include clean code through our Git/PR workflow and a concise production go-live checklist. Follow the supplied designs and existing application patterns. Avoid unnecessary redesigns or architectural changes unless technically justified and discussed first. Long-Term Opportunity If performance is satisfactory, we intend to continue working with the selected developer on a long-term basis. When Applying: Please briefly answer: 1. What Stripe subscription/billing systems have you personally implemented? 2. How do you use Claude Code, Codex, or similar tools to materially improve development speed? 3. How do you review and test AI-generated code? 4. Are you comfortable developing and testing in Stripe sandbox without production credentials? 5. What is your availability over the next few weeks?