Vesting is the mechanism that turns an equity grant into equity actually earned over time. It exists so that founders and employees are rewarded for staying and contributing, not just for showing up on day one and leaving on day two.
The common structure is four-year vesting with a one-year cliff. The cliff means nothing vests until the first anniversary, at which point a full quarter vests at once; after that, the rest typically vests monthly over the remaining three years. Someone who leaves before the cliff earns no equity at all, which is the point: it filters out the people who do not stick.
New founders are often surprised that their own equity vests, but investors usually require it, and co-founders should want it. Without founder vesting, a co-founder who quits after a few months could walk away with a huge chunk of the company, leaving the ones who stayed to build value for someone who left. Vesting protects the committed against the departed.
Some grants include acceleration, where vesting speeds up on certain events like an acquisition, single-trigger, or an acquisition plus a termination, double-trigger. These terms matter most at exit and are worth understanding before signing. This is general information, not legal advice.
Equity earned by staying, not by starting.