buddy of mine started a saas company in 2024. i did design + advisory unpaid because we were "partners." he handled product, i did marketing assets and customer interviews. talked about 15% equity verbally. never put it in writing because friends.
they just closed a $2M seed round. founder now says i was a "consultant" and offers me $5k. is anything in writing? no. but i have hundreds of slack messages where he calls me his cofounder.
this is a textbook "founder dispute" claim. without a written agreement you're relying on (a) implied partnership/joint venture theories, (b) quantum meruit for services rendered, (c) maybe promissory estoppel based on the "cofounder" promises.
screenshot EVERYTHING. slack messages, emails, github commits, anything that shows you were treated as a cofounder. that's your evidence base.
Pre-incorporation cofounder disputes are common and often resolvable because of the company's incentive to clean up the cap table. Theories of recovery: (1) implied partnership/joint venture (each partner has rights in the venture), (2) quantum meruit for value of services rendered, (3) promissory estoppel based on representations of equity, (4) breach of oral contract if the equity discussion is sufficiently specific.
The slack history is gold. Document the timeline carefully. Informational only.