From single-vendor stores to full marketplace platforms — building an eCommerce app involves far more than listing products. Here's the full breakdown every founder needs before starting.
eCommerce remains one of the largest categories we build in, and also one of the most misunderstood from a cost perspective. Clients often compare their requirements to Shopify — but custom eCommerce platforms are a completely different engineering challenge.
Single-Vendor vs Marketplace Architecture
The biggest cost fork: single-vendor (one seller, many buyers) vs marketplace (many sellers, many buyers). Marketplaces require multi-tenant product management, split payment routing, seller dashboards, commission tracking, and dispute resolution — easily 3x the complexity of a single-vendor store.
Cost by Platform Type
| Platform Type | MVP Cost | Full Build | Timeline |
|---|---|---|---|
| Single-Vendor App | $20,000–$40,000 | $60,000–$120,000 | 3–5 months |
| Multi-Vendor Marketplace | $60,000–$100,000 | $150,000–$300,000 | 6–10 months |
| B2B Commerce Platform | $50,000–$90,000 | $120,000–$250,000 | 5–9 months |
| Headless Commerce | $40,000–$70,000 | $100,000–$200,000 | 4–8 months |
Brilliant Minds has delivered eCommerce platforms generating millions in GMV for clients in fashion, electronics, FMCG, and B2B supply chain. We build for scale from day one, not as an afterthought.
Priya Nair
AI Solutions Lead, Brilliant Minds
Published 5 October 2025
