BigCommerce Developer Multi-Brand D2C Launch Custom Checkout & High-Risk Payment Integrations

We're launching a multi-brand direct-to-consumer product line consisting of adult-oriented consumables (regulated) and dietary supplements (compliant). We need a senior BigCommerce developer to build the complete e-commerce platform, including custom checkout, multi-gateway payment routing, age verification, tax compliance, and subscription infrastructure. This is a fixed-scope, milestone-driven engagement with clear compliance requirements. We are foreign-owned with a US operating subsidiary; the site will be built for the US market with international expansion planned in 8 - 12 months. We are a well-capitalized international operator entering the US D2C market with an established manufacturing partnership, a US warehouse operation, and offshore corporate structure already in place. We have committed initial marketing capital and inventory. What we need now is a best-in-class digital storefront and checkout infrastructure to support launch and scale. What We're Building Primary D2C storefront on BigCommerce Plus 5–8 initial SKUs across two product categories (adult regulated + supplements) Custom checkout using BigCommerce Checkout SDK (not the default checkout) Multi-gateway payment routing (different SKUs route to different processors based on product category) Age verification integration at checkout (AgeChecker.net or equivalent) State-based shipping restrictions (ShipperHQ or custom logic) Adult signature required workflow for shipping (integrated with ShipStation + UPS) Avalara AvaTax integration including specialty tax modules for state excise Klaviyo email/SMS integration with pre-built flows Recharge Payments subscription integration with Subscribe & Save functionality Reviews integration (Judge.me or Yotpo) Referral program integration (Refersion or Friendbuy) Multi-store or subdomain architecture (primary catalog + separately age-gated section) Google Tag Manager, GA4, Meta Pixel, TikTok Pixel with proper conversion tracking Required Skills And Experience Applicants must demonstrate: Minimum 3 live BigCommerce stores in portfolio (please share URLs, not screenshots) Experience with BigCommerce Checkout SDK and custom checkout builds Integration experience with at least one high-risk payment processor (PaymentCloud, Soar Payments, Corepay, NMI, Authorize.net, Durango, or equivalent) Proven experience with multi-gateway routing logic — routing transactions to different processors based on cart contents or SKU category Prior work with Stencil theme framework Experience integrating Avalara AvaTax on BigCommerce Experience with ShipStation, ShipperHQ, and adult signature shipping workflows Klaviyo + Recharge integration experience on BigCommerce specifically (integration differs from Shopify) Strong front-end skills (HTML/CSS/JavaScript, Handlebars templating) API integration experience (REST, GraphQL, webhooks) Preferred / Bonus Experience Prior work with nicotine, vape, CBD, kratom, supplements, or adult products Experience with age verification (AgeChecker.net, BlueCheck, Veratad) Familiarity with FDA warning label requirements and Prop 65 implementation Crypto payment gateway integration (BitPay, NOWPayments, Coinbase Commerce) Fluency with Google Analytics 4 enhanced e-commerce tracking Background in D2C conversion optimization and mobile-first design Deliverables Fully functional BigCommerce Plus storefront on our custom domain Custom checkout with multi-gateway routing and age verification All integrations listed above, fully configured and tested Mobile-first responsive design passing Core Web Vitals Admin training documentation (written + Loom videos) for our team 30-day post-launch bug fix support included Full handover of code repository, credentials, and asset files Signed NDA and IP transfer agreement upon final payment Timeline Discovery and design phase: 2 weeks Development phase: 5–6 weeks QA, content loading, and launch prep: 1–2 weeks Total project duration: 8–10 weeks from kickoff Target launch date: [date approximately 10 weeks from posting] Budget $6,000–$10,000 fixed fee, milestone-based payment (25% kickoff, 25% design approval, 25% development completion, 25% launch). Agency proposals outside this range will be considered if the premium is clearly justified by scope efficiency, team composition, and portfolio depth. We are quality-first but disciplined — the best proposals demonstrate scope efficiency, not scope inflation. How To Apply Please respond with the following (applications missing any of these will not be reviewed): Three BigCommerce store URLs you have built or significantly contributed to A brief description (200 words max) of the most complex custom checkout you have built, including which payment gateways you integrated and how you handled routing logic Your experience with regulated product categories (nicotine, vape, CBD, supplements, adult) — be specific about what you built Your proposed approach to multi-gateway routing for a store selling both regulated adult products and standard supplements (2–3 sentence overview) A written proposal with your timeline, milestone breakdown, and fixed-fee quote Two client references from past BigCommerce projects (we will contact them) Your availability and preferred communication cadence In your proposal, please open with the phrase "Regarding your multi-gateway routing requirement" followed by your specific approach. This helps us identify applicants who have carefully read the brief. We will shortlist within 5 business days and schedule discovery calls with 3 finalists. We are ready to sign with the chosen candidate within 14 days of posting. Serious applicants only. This is a professional engagement with a well-defined scope and clear budget. We are not looking for the cheapest option we are looking for the right partner.