/01 Delta Group
PostMost
/02 Overview
PostMost is a reseller operating system. Instead of logging into eBay, Etsy, Poshmark, Mercari, Depop, and a half-dozen other marketplaces to list the same item, a seller creates one listing in PostMost and cross-posts it everywhere in a single workflow.
/03 The Challenge
Resellers waste hours copying photos, titles, and descriptions between platforms, then manually tracking inventory and sales across disconnected dashboards. One item can live in ten places, and a sale on any platform has to be reflected everywhere else.
We needed a platform that could centralize listing creation, handle marketplace-specific fields and rules, remove image backgrounds at scale, store photos in durable object storage, and queue cross-post jobs reliably without blocking the user interface.
/04 Architecture
Next.js Frontend
The dashboard and listing form are built with Next.js 14 App Router, TypeScript, Tailwind CSS, and shadcn/ui. Server Actions handle form submission, validation with Zod, and marketplace adapter calls, keeping the UI responsive and type-safe.
Prisma + Neon
Prisma ORM on Neon PostgreSQL manages listings, platform listings, cross-post jobs, and usage credits. Row-level isolation keeps each seller's data separate, and a direct connection handles migrations while pooled connections serve runtime traffic.
Marketplace Adapters
A standardized adapter interface wraps API-enabled marketplaces like eBay and Etsy and provides Playwright-ready stubs for automation platforms. New marketplaces are added by implementing a single interface, not by branching the entire codebase.
Jobs, Storage & AI
Cross-post jobs are written to Postgres and drained by a Vercel cron, with exponential backoff and atomic claim logic. Photos are uploaded directly to Cloudflare R2 via presigned URLs to avoid serverless body limits. Background removal uses fal.ai BiRefNet or PhotoRoom, metered independently from listing credits.
/05 Key Features
- Universal listing form that normalizes product data across every supported marketplace.
- Cross-post queue with status tracking, retry logic, and a durable Vercel cron backstop.
- Marketplace adapter pattern for eBay, Etsy, Poshmark, Mercari, Depop, Facebook Marketplace, Craigslist, OfferUp, Vinted, and Grailed.
- AI background removal with provider fallback and per-plan usage metering.
- Presigned R2 uploads so browsers push photos directly to object storage without proxying through the server.
- Stripe billing for usage credits and monthly listing limits.
- Browser extension for syncing external marketplace sales back into the central inventory.
/06 Initialization