Interview Mastery: PHP & Backend Engineering.
125 questions. Every one answered at Junior, Middle, and Senior depth, with a Senior Probe follow-up that goes to the internals. Prep material if you're interviewing. A calibration rubric if you're hiring.
Written by Abdulloh Abdusamadov — backend engineer, 2+ years shipping production PHP systems.
Every question, answered four ways.
Not a Q&A list — a rubric. Each of the 125 questions is answered at three deliberately calibrated depth levels, then pushed one step further with a Senior Probe: the follow-up a strong interviewer asks after the first answer, taken down to opcode behavior, algorithmic complexity, and real production tradeoffs.
Correct, surface-level.
Reasoned, contextual.
Tradeoffs, production.
Internals, code-level.
Sample Question
An illustrative example in the book's format — module and phrasing are representative, not one of the actual 125 questions.
What happens internally when you assign one PHP array to another variable?
PHP copies the array, so changing one doesn't affect the other.
It's Copy-on-Write — both variables reference the same zval until one is mutated, at which point PHP allocates a separate copy for the write.
Same mechanism, plus the performance implication: passing large arrays around is cheap until the first write, which is why refcount-heavy code paths can spike memory unpredictably under load if you're not aware of where the copy actually triggers.
How would you confirm Copy-on-Write is actually happening for a given array, at runtime?
Inspect the refcount with debug_zval_refcount(), or
use xdebug_debug_zval() — the count drops to 1 the
moment a write forces the copy to split.
125 Questions, 5 Modules
25 questions per module. Module 5 closes with 10 full end-to-end system-design capstones.
Zend Engine mechanics, zval and Copy-on-Write, GC, the type system, closures, enums, Fibers, OPcache/JIT, attributes.
Indexing, isolation levels, MVCC, joins, Redis internals, distributed locking, cache stampede protection, connection pooling.
REST design, queues, sagas, CQRS, event sourcing, circuit breakers, distributed tracing, WebSockets/SSE, PHP-FPM vs. Swoole.
Password hashing, XSS/CSRF, RBAC/ABAC, TDD and mutation testing, profiling, Docker, CI/CD, secrets management, zero-trust, disaster recovery.
OOP fundamentals, DI/service containers, GoF patterns, DDD, Reflection/Attributes — plus 10 full system-design capstones: URL shortener, payment gateway, multi-tenant SaaS, real-time leaderboards, and more.
One Book, Two Jobs
The same 125 questions do double duty — sharpen your own answers, or standardize how your team scores everyone else's.
Know what a Senior answer actually sounds like — before you're asked to give one.
You get all 125 questions pre-scored against real interview tiers, so you can see exactly where a "correct" answer stops and a "hire" answer starts — and you walk in already able to handle the Senior Probe follow-up, not caught off guard by it.
A ready-made scoring rubric, so every interviewer on your team scores the same answer the same way.
You get 125 pre-built questions with calibrated answers at every level plus a built-in follow-up for each one — no more improvised probes, no more one interviewer's "strong hire" being another's "meh."
Interview tomorrow? Grab the free 2-page cheat sheet.
A separate, standalone resource — not an excerpt from the book. Two pages, fast to skim, built for when the interview is close and you need a quick refresher, not a study plan.
Applying for a role with weeks or months of runway to prepare? That's what the book below is for. Interview's tomorrow? This is.
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Interview Mastery: PHP & Backend Engineering
125 questions across PHP internals, databases, architecture, security, and system design — each answered at Junior, Middle, and Senior depth with a Senior Probe follow-up.
Linear Code Mastery: 100 Progressive Problems for PHP
Prefer building over drilling questions? 100 progressive coding problems for hands-on backend practice.
Questions? Let’s Connect
Have questions about the book, want to bulk-order for a hiring team, or just want to talk PHP? Reach out across any of these channels.