What are the real costs and margins on ONDC compared to Amazon and Flipkart?

There's no single ONDC commission rate, your actual cost is the fee your chosen seller app (Mystore, Fynd, etc.) charges plus logistics, which several claim is meaningfully lower than Amazon or Flipkart's stacked commission-plus-fulfilment fees, but published numbers vary a lot by app and category. Because pricing transparency is still a known weak point of the network, get a written fee breakdown from your seller network participant before committing rather than relying on marketing claims. Model ONDC as a smaller, cheaper-per-unit-but-lower-volume channel next to your marketplace numbers, not a like-for-like replacement.