FAQ

What Happens to Custom Software If the Developer Leaves?

SaaS Displacement

Key Takeaways
  • "Bus factor" is the number of people who could be hit by a bus before a project stalls.
  • PRJ-01 -- a 194,954-line operations platform replacing six SaaS vendors -- was built on PHP/Laravel 10.

If the developer leaves and the codebase is on a standard framework, version-controlled, and documented, another developer can take over. The business keeps running. If the codebase is proprietary, undocumented, or locked to a single person's knowledge, the business has a serious problem. The difference is how the software was built, not whether it was custom.

This is the "bus factor" question

"Bus factor" is the number of people who could be hit by a bus before a project stalls. A bus factor of one means the entire system depends on a single person. This is a legitimate concern for any custom build -- but it is also a concern that has well-known solutions.

According to a 2023 GitHub Octoverse report, over 97% of software projects use open-source components and standard frameworks. That means the skills required to maintain most custom software are transferable. A system built on Laravel (PHP), React, or Django is maintained by the same pool of developers who maintain millions of other systems built on those same frameworks.

What the documented build looks like from a handoff perspective

PRJ-01 -- a 194,954-line operations platform replacing six SaaS vendors -- was built on PHP/Laravel 10. Here is what a replacement developer would inherit (CS10, portal_stealth_locked_values, audited February 2026):

  • Framework: Laravel 10 -- one of the most widely adopted web frameworks globally
  • Version control: 1,394 commits in git, full history preserved
  • Database schema: 135 tables, 112 Eloquent models (Laravel's standard data layer)
  • Code structure: 104 controllers, 59 service files, 64 console commands -- all standard Laravel conventions
  • Architecture: RBAC with multi-tenant data isolation, 4 user roles, 5 portal types

A competent Laravel developer can read this codebase, trace any feature through controllers to services to models, and make changes. The operator -- Michael George Keating -- chose to build alone. The system does not require a single operator to function (CS10).

How to reduce bus factor before it becomes a problem

Use a standard framework. If the software is built on a framework with a large developer community, the hiring pool for maintenance is deep. Laravel alone has over 75,000 GitHub stars and an active ecosystem of developers worldwide.

Keep everything in version control. Every change, every decision, every rollback is in the git history. A new developer can trace the evolution of any feature.

Build on conventions, not cleverness. Standard file structures, naming patterns, and service layers mean a new developer does not need a personal tour of the codebase. They can follow the framework's conventions and find what they need.

Document the architecture, not just the code. The documented platform includes explicit architecture records: database table counts, integration maps, service layer inventories, and a complete locked values file cross-referenced against production data. This is the kind of documentation that makes handoff realistic rather than theoretical.

The bus factor risk is real. But the mitigation is engineering discipline, not staying on rented SaaS platforms. A vendor can also sunset a product, get acquired, or pivot -- and when that happens, the business has no source code to hand anyone.

Related: Can one person maintain a custom-built business platform? | What are the risks of building and owning your own business software?

References

  1. GitHub (2023). "Octoverse Report." Open-source adoption rates and framework standardization benchmarks (97% of projects use open-source components).
  2. Keating, M.G. (2026). "Case Study: The Platform Displacement." Stealth Labz. Read case study