Founders Bar

This is the single most on-point read for your question: it explains bus factor and lays out six concrete ways to stop one developer from becoming a single point of failure. It covers documentation, code reviews, standard architecture, IP and notice clauses, and bringing in a second reader before you need one. Treat it as your mitigation checklist.

Bus Factor: The Silent Startup Killer

From Founders Bar by Aneesh Mohanachandran 12 min read

• Never let bus factor equal one, build redundancy from day one
• Architecture decision records and video walkthroughs preserve knowledge if the person leaves
• The real risk is not headcount, it is whether the knowledge survives a departure