Hiring & Engagement
A senior software engineer is a technologist with at least six years of professional experience who can lead the design and implementation of production systems independently. Senior engineers own architectural decisions, mentor junior teammates, and operate the systems they build. They don't just write code to a spec.
At a glance
Definition
The 'senior' label gets applied loosely across the industry, so it's worth being precise about what it means. At Prosigns, a senior software engineer has six or more years of professional engineering experience, has shipped at least one production system from concept through operation, can decompose ambiguous business requirements into a technical plan, and can be trusted to make architectural calls without needing committee approval for every decision.
§01
Three behaviors separate seniors from mid-level engineers: (1) they say no to bad designs early, including their own previous ones: saving teams from rebuilds; (2) they think in trade-offs, not in best practices, because they've seen the same 'best practice' fail in two different contexts; (3) they own outcomes, not tasks. A senior won't ship a feature they know is wrong, even if it matches the ticket.
§02
On a senior-only team, every code review surfaces design issues before they ship. Estimates are calibrated by experience, not optimism. The Slack channel for 'I'm stuck' is mostly empty because problems get unblocked at the keyboard. Architectural decisions reflect operational consequences, because everyone has been on call. Mid-level and junior engineers add capacity, but they don't add this, and the work output of a senior-only team is qualitatively different, not just faster.
Approach
Every engineer on a Prosigns engagement has six or more years of experience. We don't subcontract, we don't use offshore vendors, and we don't put junior engineers on client work. The bench you see in the proposal is the bench in production. Average tenure is 5.2 years and we publish that openly. Engagement models, fixed-scope, embedded teams, managed services, are documented at /engagement-models/, and the seniority bar is the same across all three.