How do you structure equity splits in a 3-founder startup pre-seed with unequal contributions?

Went through almost exactly this in 2021 — two technical founders (one full, one 20hrs/week) plus a commercial co-founder who closed our first $40k pilot. Here's what we learned the hard way. The split we landed on after three weeks of uncomfortable conversations: 42 / 28 / 30. Full-time technical got the anchor, part-time technical took a meaningful discount with a conversion clause (if he went full-time within 12 months, his stake stepped up to 35 and mine adjusted down proportionally), and the commercial founder got 30 because one client is not a business — but his network was the actual asset, not the deal itself. We valued future contribution more than past contribution, which is the right frame at pre-seed. On vesting: do not go into a $500k raise without a signed agreement. Not because investors always demand to see it — some won't — but because the conversation gets 10x harder once there's money in the account. We had one founder leave 8 months in. Without a cliff, he would have walked with his full stake. With a 12-month cliff and 4-year vest, he left with nothing vested, we had clean cap table, and the investor didn't blink. That one clause saved the company. The specific landmine you're walking into: the part-time founder's unvested equity sitting on the cap table makes your lead investor nervous because it's a future dilution wildcard they can't model. They'll either ask you to resolve it pre-close or price the risk into the valuation. Either way you lose. Get the agreement signed in the next two weeks, not after the term sheet. One more thing — the business co-founder sourcing one client is a contribution, but make sure your agreement distinguishes between equity for past contribution vs equity for ongoing role. If his role post-raise is primarily sales and BD, tie a portion of his stake to a performance milestone (e.g., $X ARR within 18 months) rather than pure time-based vesting. Unusual but not unheard of at this stage, and it aligns incentives cleanly.