Contact person: Backend Developer for Shopify SaaS

Phone:Show

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Location: Melun, France

Budget: Recommended by industry experts

Time to start: As soon as possible

Project description:
"1) Context & Objective I already provide the frontend (landing + dashboard) and all FR/EN content. I am looking for a backend developer to connect all APIs and deliver a mobile-first SaaS that creates ready-to-use Shopify mono-product stores, with options to add physical products. Important: We use Shopify via a Partner account, not an app published on the Shopify App Store. Subscription payments are handled outside Shopify (Stripe / Lemon Squeezy). The SaaS must remain minimalistic and very fast. I will provide the GitHub repository for the frontend. The developer’s only job is to implement the backend and connect all APIs. 2) User Journey (Functional Flow) Landing Page User chooses a niche in a text field (suggestions displayed but not mandatory). CTA: “Create My Store – €79.99/month.” Google login, then Stripe checkout (single recurring plan €79.99/month). Pricing section visible: explain that the store will include fictitious digital products for preview, then the user can add physical products (free option via partners or premium option via DSers). Footer link: “Become an Affiliate” pointing to /affiliates. After Payment Creation/connection of a Shopify store via Shopify Partner (dev store that becomes live). Install a free Shopify theme (e.g., Dawn). OpenAI automatically generates: store name/slogan, About page, banner text, and fictitious digital product pages. These fictitious digital products are only placeholders, but they give the user a full overview of the storeand serve as inspiration for what physical products they might later add. Users can freely replace or edit these products when they choose their actual physical catalog. Push all this into the store via Shopify Admin API. Dashboard (ultra minimalistic) Header: “Your Store is Ready.” Only two main blocks: Free Option – Partner Products: add physical products from our partner stores (backend call injects catalog). Paid Option – DSers: “Connect DSers” button with our company affiliate link. Two small secondary links: “Customize IA Design” and “Regenerate IA Texts.” Anti-churn banner: “You can generate a new store anytime.” Languages FR/EN switch in header. Whole site switches language. No mandatory auto-detection. 3) Developer Missions (Backend Work) A. Authentication & Database Firebase Authentication (Google sign-in) and Firestore (or RTDB). Minimal tables/collections: users: uid, email, language, subscription status, token_quota. stores: user_id, shopify_store_id, domain, state (dev/live), niche, created_at. usage: user_id, tokens_used_month, resets monthly. logs: main events (payment success, store creation, errors). B. Subscription (Stripe) Single recurring plan: €79.99/month. Webhooks: [login to view URL] → activate subscription + trigger store creation. invoice.payment_succeeded / …failed → update users.subscription_status. User can cancel subscription inside dashboard (via Stripe API). C. Shopify Partner (mandatory) Configure a Shopify Partner account (access provided). OAuth Partner to create/link a dev store to user’s account. Install free theme (Dawn) and push: Home page: slogan, banner text. About page. 1 mono-product digital product (title, description, placeholder image if needed). These digital products are fictitious and generated by OpenAI to provide an overview and inspiration. Important: we do NOT publish an app on the Shopify App Store. Partner + Admin API only. D. OpenAI (text + fictitious products generation, minimal cost) Generate short texts in FR/EN: Store name, slogan, About, digital product description, banner text. Generate fictitious digital product pages (title, description, mock content). These fictitious products help users visualize their store and decide later on real products. Quota: 5,000 tokens per month per user (in/out combined). Store and decrement in usage. Block politely if exceeded. Endpoint for regeneration of texts and products. E. Physical Products Free Option – Partner Products: Button “Add My Free Products.” Backend endpoint injects a partner catalog (our stores) into user’s Shopify store. The order payment goes directly to the partner, not through our SaaS. Paid Option – DSers: Button “Connect DSers” redirects to our company affiliate link. If DSers API allows, implement minimal connection. Otherwise simple redirect. F. Affiliation (Lemon Squeezy) Subscriptions sold via Stripe, but affiliate program run with Lemon Squeezy. Integrate Lemon Squeezy tracking script to attribute sales correctly. Add page /affiliates and footer link “Become an Affiliate.” One-time €50 per confirmed subscriber (no recurring to affiliates). G. Internationalization Use two JSON files ([login to view URL], [login to view URL]). Switch toggles all content (landing, pricing, dashboard, affiliates page). Backend generates IA texts and fictitious products in correct language. H. Security & Compliance Never expose API keys to frontend. Store secrets in environment variables. Verify signatures on webhooks (Stripe, Lemon Squeezy). Apply rate limiting per IP/user on IA generation endpoints. Centralized error logging. I. Minimal Admin Internal protected page (or scripts) for: Search user, view subscription status, reset monthly tokens. Replay store creation if failed. J. Deployment Firebase Hosting for frontend, Cloud Functions/Run for backend. Environments: dev and prod. Provide clear README (env vars, commands, endpoints). 4) APIs & Required Tech Firebase: Auth (Google), Firestore, Hosting, Functions/Run. Stripe: €79.99/month plan, webhooks, cancellation. Shopify Partner + Admin API: OAuth, dev store creation, theme + content push, mono-product with fictitious digital products. OpenAI: text + fictitious product generation, 5k tokens/month/user. DSers: company affiliate link (or API). Lemon Squeezy: affiliate tracking, €50 one-time payout, affiliates page. 5) What NOT to Do Do not publish in Shopify App Store. Do not process ecommerce payments inside SaaS (partner sales handled externally). Do not exceed scope of IA (short texts + fictitious product generation only). Do not change frontend structure (I provide it). 6) Backend Endpoints (Example) POST /api/checkout/create-session → creates Stripe checkout session. POST /api/webhooks/stripe → manage subscription state, trigger store creation. POST /api/shopify/create-store → create/link user dev store. POST /api/shopify/push-theme → install theme + push base content. POST /api/openai/generate → generate texts + fictitious products (check quota). POST /api/products/partners/add → add partner products. GET /api/user/me → return user profile, subscription, quota. POST /api/user/cancel → cancel Stripe subscription. POST /api/affiliates/track → if needed, relay info to Lemon Squeezy. 7) Environment Variables FIREBASE_PROJECT_ID STRIPE_SECRET_KEY, STRIPE_WEBHOOK_SECRET, STRIPE_PRICE_ID SHOPIFY_PARTNER_API_KEY, SHOPIFY_PARTNER_API_SECRET, SHOPIFY_PARTNER_REDIRECT_URI OPENAI_API_KEY DSERS_AFFILIATE_LINK LEMON_SQUEEZY_SCRIPT_URL / keys APP_BASE_URL JWT_SECRET (if needed) 8) Success Criteria Real user can: Login with Google, Pay €79.99 via Stripe, Get a Shopify mono-product store with theme, IA texts, and fictitious digital products, Access dashboard with two clear options (Free Partner Products / DSers Paid), Regenerate IA texts and fictitious products in chosen language, See monthly quota (5,000 tokens) enforced, Cancel subscription, Switch FR/EN. /affiliates page works. Stripe webhooks reliable. Clear README with setup instructions. 9) Security & Performance Server-side API keys only. Webhook signature checks. Rate-limiting. No sensitive data in plain DB. Proper error handling (simple messages to users, detailed logs server-side). 10) Timeline Since frontend is ready, target 4–6 working days for V1 backend if fully dedicated. Add 1–2 days for final testing & fixes. 11) Developer Requirements Verified experience with Stripe, Shopify Partner/Admin API, Firebase, OpenAI. Ability to deliver clean backend (documented endpoints, README). Understands minimalism and robustness. 12) Key Reminders Shopify Partner yes, App Store no. Start with fictitious digital products (legal/clean, for inspiration). Two product options: free (partner catalog), premium (DSers). Single plan €79.99/month, cancellable anytime. IA tokens: 5k/month/user. Affiliation: €50 one-shot via Lemon Squeezy. 13) Languages & Tools used in the project (IMPORTANT – read before applying) This project uses the following languages and frameworks: 1. TypeScript (.ts / .tsx) • The developer only needs to understand them and connect the backend. 2. React.js • The frontend is built with React (.tsx files). • No need to rebuild the UI, but you must know how to connect APIs to existing components. 3. Node.js • This will handle business logic and connect all APIs. 4. Firebase • For authentication (Google Sign-in). • For database (Firestore or Realtime DB). • For Cloud Functions (serverless backend). 5. Stripe API • To manage the unique recurring subscription plan (€79.99/month). • Includes payments integration + webhooks (activate/deactivate accounts). 6. Shopify API (Admin + Partner API) • To automatically create/configure Shopify stores. • This is NOT a public Shopify App → it’s an integration via Shopify Partner. 7. OpenAI API • To generate fictional digital products for store previews. • This gives users an overview of their store before they connect real products (via DSers or other apps). 8. LemonSqueezy API • To manage influencer affiliate payouts. - One-time payout of €50 per referred paying user. 9. TailwindCSS 10. [login to view URL] This makes it 100% clear so no developer is surprised later. This document is the exact scope. If something is unclear, the dev must ask before coding. Deliverable: backend fully connected, working, with README and env var list." (client-provided description)