Why isn’t [niche platform] included?

The 5 platforms in the calculator (Magento Open Source, Adobe Commerce, Shopify Plus, BigCommerce, SFCC) cover ~85% of mid-market and enterprise commerce decisions in 2026. Niche platforms get omitted for one of three reasons:

• Adjacent but smaller market — Centra, Spryker, commercetools, Saleor, Medusa.js, Sylius. These show up in re-platform shortlists at <5% frequency in my data. If you’re seriously evaluating one, send the inputs and I’ll add it to the calibration.
• Plugin-not-platform — WooCommerce, PrestaShop, OpenCart. WooCommerce is on the form (because it’s common as a current-platform “source”), but I don’t calculate WooCommerce as a destination because it’s a WordPress plugin and TCO is dominated by WP hosting + plugin stack rather than the commerce layer.
• Dying stacks — Magento 1, OpenCart, X-Cart, ZenCart. If you’re here you’re leaving them, not migrating to them.

Headless setups (Magento + Vue Storefront, Magento + Hyvä headless, BigCommerce + Next.js, commercetools + custom front-end) aren’t separate platforms in this calculator — they layer on top of one of the 5 and add ~$30k–$80k upfront + ~$15k–$40k/yr ongoing for the front-end. Use the calculator for the platform layer; add headless cost separately.