Sendcore

Build me a private Shopify campaign sender for one store I already own. Not a SaaS, not multi-tenant, no signup. Requirements: - Node 22 + Fastify + better-sqlite3, server-rendered HTML, no client framework. - Read the store with a Shopify custom app Admin API token I create myself (read_products, read_customers, read_orders); no OAuth, no App Store install flow. - Send through one bulk email provider with my API key and my already-authenticated sending domain; both in .env, ship a .env.example. - SQLite tables: contacts (email, consent state, source, created_at), products cached from Shopify, campaigns (subject, body_html, status, sent_at), and sends (contact_id, campaign_id, status, error). - Every contact carries an explicit consent state. Never send to an unsubscribed or unconsented contact, and prove that with a test. - Every email gets a working one-click unsubscribe link plus List-Unsubscribe headers, backed by a signed token and honoured immediately. - The composer is a plain HTML textarea plus a product picker that inserts image, title, price, and link from the synced cache. Render with inline styles and a table layout so it survives Gmail and Outlook; no external stylesheets or web fonts. - Always send a test to myself first, and require a typed confirmation of the recipient count before any real send. - Send in batches with retry and backoff, one send row per recipient, so a crash resumes instead of double-sending. Report delivered and failed from the sends table only; do not invent open or click tracking. - CSV import and export for contacts so the data is never trapped in the app. - Tests: the consent gate, the unsubscribe token, batch resume, and one end-to-end campaign against a mocked provider. - README states what this is not: no deliverability operations, no bounce or complaint processing, no App Store distribution, no billing. Say plainly that real volume from a cold domain lands in spam, and warmup is now the reader's job.