This is not a contract and there is nothing here to sign. It is the list of questions that, left unasked, is what actually breaks projects apart.
Written down does not mean expensive. An email that both people reply “agreed” to is written down. A shared document with both names and the date is written down. What matters is that in six months there is something to read instead of two different memories.
Code, designs, copy and drawings belong to the person who made them unless something in writing says otherwise. Paying someone does not automatically change that, and neither does promising them equity.
A developer builds the app over four months for a share of the company. He leaves after a disagreement. He still owns the code. The founder cannot legally ship it.
"Equity" and "a share" are not amounts. Two people can shake hands on the same words and mean numbers that are ten times apart.
The founder means 5% once the company is registered. The contributor understood 20% starting immediately. Neither wrote it down. Both are certain they are right.
Without this, nobody can tell the difference between someone who is behind and someone who has quietly stopped.
Three months pass. The founder thinks the app is nearly finished. The contributor thinks they agreed to "help out when free" and has done six hours.
Most of these arrangements end early. That is normal and not a betrayal — but if the ending is not agreed while everyone is still friendly, it gets agreed while everyone is angry.
A contributor with 20% stops replying after month two. Years later the company raises money and he still owns 20% for two months of work.
Some of what a contributor sees is genuinely commercially sensitive. Some of it is not. Agreeing which is which prevents both a real leak and an unfair accusation.
A contributor uses the same general approach on an unrelated job. The founder believes the idea was stolen. Nothing was ever written down, so neither can prove anything.
Deciding this in advance is what keeps a disagreement from becoming a court case. It costs nothing to write and it is the line people are most grateful for later.
A $4,000 disagreement turns into $40,000 of legal fees, because neither side had agreed on a single step to take before "see you in court".
Plenty of small businesses start on a clear email between two people who trust each other, and never need more than that. But there are three moments where the cost of being wrong jumps, and a one-off review by a real lawyer is worth it:
Ask for a fixed-fee review rather than hourly work. You are asking someone to read a short agreement once, not to represent you.