Senior WordPress/PHP Developer needed, Custom Enrollment Portal with DocuSign & Stripe

Hi there, I read through your full spec and I know exactly what this needs to be. You're not asking for a website with plugins. You're asking for a custom enrollment system that handles legal signatures, payments, and pre-filled company data without leaking anything client-side or breaking during the ceremony. The risk here isn't coding. It's launching August 31st with something that fails on the DocuSign callback, exposes company records in a form field, or lets someone skip the scroll enforcement on terms. I'd guess you've seen enough agency handoffs to know the difference between something that demos well and something that actually ships clean. Here's the build: 1. Custom plugin architecture. One plugin handles the entire flow. Custom database table for the 2,500 company records with lookup by access code, server-side only. No data pre-fills client-side. The form pulls company info via AJAX after code validation, sanitized and nonce-protected. WP REST API endpoints for the multi-step form state, all locked down with proper auth. 2. DocuSign integration. I've integrated DocuSign eSignature API twice before, both times handling OAuth 2.0 with JWT for service account access and token refresh logic stored securely. Pre-fill the template with company data server-side, generate the signing ceremony URL, embed it cleanly. Webhook listener for envelope status (completed, declined, voided) with HMAC signature verification. No guessing on status, everything confirmed server-side before marking enrollment complete. 3. Stripe Checkout for the two paid services. Redirect flow, success/cancel handlers, webhook listener for payment confirmation. Again, HMAC verified. No enrollment marked complete until both signature and payment (if applicable) confirm. 4. Admin dashboard. Custom post type or dedicated admin page for managing access codes, CSV import/export for bulk operations, region eligibility filtering. Clean, simple, no page builder garbage. 5. Security. Nonces on every form, input sanitization, parameterized queries, rate limiting on the access code lookup, hardened permissions. This site handles legal docs and payments. I treat it that way. I can start immediately. My preference is hourly at $85/hr. Based on your 100-130 hour estimate, that puts this in the $8,500-$11,050 range. I'll track transparently and keep you ahead of any scope creep. Three answers you asked for: (1) I built a custom LearnDash extension for The Mama Coach that triggered WooCommerce one-click upsells on course completion. Existing plugins either fired too early, didn't pass the right user meta, or required the student to re-enter payment info, which killed conversion. I hooked into learndash_course_completed, queried custom course meta to determine which upsell offer to show, then generated a tokenized WooCommerce checkout link pre-filled with the student's saved payment method. Conversion rate on the upsell went up 40% because friction dropped to one click. (2) I've integrated DocuSign eSignature API and Zoom API, both OAuth 2.0 with JWT. For DocuSign, I used JWT grant for service account access, stored the token securely in wp_options with expiration timestamp, and built a refresh handler that fires automatically when the token is within 10 minutes of expiry. For webhooks, I verify the HMAC-SHA256 signature DocuSign sends in the X-DocuSign-Signature-1 header against the payload and my Connect key. No webhook gets processed without passing that check. Same pattern for Stripe webhooks, always verify before trusting. (3) Custom table in the WordPress database, something like wp_enrollment_companies. Columns for company name, address, region, access code (hashed or indexed), and any other pre-fill data. Access code lookup happens entirely server-side via AJAX. User submits the code, PHP queries the table, returns only the matching company data if valid, otherwise error. The 2,500 rows never touch the DOM, never get embedded in JavaScript, never get exposed in page source. Query with $wpdb prepare() for SQL injection protection. I've done three LearnDash builds where the enrollment and upsell flow mattered more than the LMS itself. This has the same structure, just with DocuSign and Stripe instead of course progression. The principles are identical: multi-step user flow, third-party API dependencies, payments, and zero margin for failure on launch day. One question: do you already have the DocuSign developer account and Connect webhook URL set up, or do you need me to handle that configuration as part of the build? Trust, Tai