Senior and staff interview questions
This course covers the questions asked in senior and staff Rails interviews, using one system throughout: Meridian, a B2B invoicing SaaS on Rails 8, PostgreSQL and Solid Queue. It explains the four signals interviewers listen for and how design rounds are scored. It works through scaling questions on replicas, shards and caches, observability with SLOs and error budgets, and technical debt with strangler fig upgrades. It also shows how to answer "it depends" with a variable, a default and a reversal condition, and ends with a scored mock loop.
What you'll learn
- ✓The four signals senior interviews score: scope, ambiguity, direction and judgment
- ✓How design rounds weigh requirements, architecture, deep dive and trade-offs
- ✓The order for scaling Rails, from measuring queries to replicas and shards
- ✓Turning an availability promise into SLIs, SLOs and an error budget policy
- ✓Stating technical debt as a cost and planning strangler fig upgrades
- ✓Answering "it depends" with a variable, a default and a reversal condition
What senior interviews measure
"This endpoint is slow. What would you do?"
Read the full lesson free →Curriculum
7 lessonsWhat senior interviews measure
How senior and staff interviews differ from earlier levels, the rounds to expect and the four signals scored.
Architecture questions and trade-offs
How design rounds score requirements, architecture, deep dive and trade-offs, using Meridian's nightly invoice generation as the example.
Scaling Rails questions
Finding the binding constraint, when read replicas and shards make sense, and the trade-offs of the Solid stack.
Observability and incident questions
Defining SLIs, SLOs and error budget policies, instrumenting four signals, debugging live incidents and writing blameless postmortems.
Technical debt and upgrade questions
Stating debt as interest in business units, sorting it into three kinds and upgrading Ledgerly with strangler fig.
Answering "it depends" well
Turning "it depends" into a named variable, a default and a reversal condition, and handling interviewer pushback.
Senior mock: putting it all together
A five-round mock loop against Meridian with weak and strong answers and a six-signal self-scoring table.