When you’re launching a multi-vendor marketplace the first decision is **“buy vs. build.”** If speed-to-market and small budget matter most, start with an out-of-the-box SaaS platform such as **Sharetribe Go** or **Arcadier**—both give you vendor onboarding, catalog, order routing and Stripe Connect payouts in a day, and you can theme them without touching code. Once you find product-market fit, graduate to a more extensible “headless” stack: **Sharetribe Flex, Mirakl, Marketplacer** or **CS-Cart Multi-Vendor** all expose APIs so you can plug in a React/Next.js front-end, CMS, Algolia search and your own micro-services without rewriting core marketplace logic. For sellers who already run Shopify, a “Shopify Plus + Marketplace-app” approach (e.g., Multi-Vendor Marketplace or Marketcube) lets you inherit their existing product data and POS while you handle order splitting and commission payouts. At enterprise scale, teams often compose a custom stack around **Stripe Connect (payments & KYC), TaxJar or Avalara (tax compliance), SendGrid/Customer.io (notifications),** and a GraphQL gateway that unifies product, inventory and pricing data.

Regardless of platform, insist on five non-negotiables: (1) programmatic vendor onboarding with KYC and split-payment support; (2) granular catalog and inventory permissions per seller; (3) order-routing logic that can handle partial fulfilment and returns; (4) escrow or delayed payout controls to reduce fraud; and (5) a vendor analytics dashboard so sellers can optimise listings. Start lean—use a SaaS marketplace engine until you’re processing a few million in GMV—then refactor the pieces that limit growth; this staged path avoids six-figure custom builds before you’ve proven liquidity on both sides of the market.