PHP backend work rewards people who can move between the request lifecycle, database behavior, caching, security, and deployment details. The reading map below is organized around those connections rather than around a pile of separate topics. Interview question sets are useful as checkpoints, but they work best after the underlying ideas have been studied in context.
Interview material as a checkpoint
Advanced PHP and junior architect interview sets, big-company PHP interview summaries, and a Tencent backend early-batch interview retrospective are useful for spotting gaps. Use them to diagnose weak areas: runtime knowledge, HTTP, MySQL, Redis, framework internals, or system design. Do not turn a question bank into the whole study plan.
The PHP runtime underneath
A solid backend engineer should understand what happens between a request arriving and a response leaving. Topics worth reading include Zend GC, PHP 7's garbage collection changes, the PHP lifecycle, dependency injection in PHP, and the lower-level execution model. These ideas explain memory behavior, extension design, and why frameworks make some choices.
Nginx and PHP-FPM
Read about the two ways Nginx and PHP-FPM communicate, how Nginx and FPM work together, FastCGI characteristics, and comparisons between the communication methods. This is the layer where many production issues begin, from timeouts to buffering and process management.
Object-oriented design that holds up
A useful cluster covers the strategy pattern, the difference between composition and inheritance, class composition and inheritance, the six design principles, and a design pattern tutorial. The goal is not to memorize pattern names but to recognize when inheritance becomes a liability and when a smaller collaborating object is clearer.
Composer and autoloading
Read about Composer autoloading and autoload implementation in PHP extensions. Autoloading looks simple until a project grows, so understanding the mechanism helps with debugging, performance, and package structure.
Sessions, cookies, and single sign-on
Cover cookie and session fundamentals, Session principles and security improvements, Session mechanics, SSO login and logout, a simple SSO implementation for PHP, and comparisons of SSO solutions. This area connects user experience with security boundaries and state management.
Web security fundamentals
Review how PHP web applications avoid XSS attacks, how to filter user input, and general filters for injection and XSS. Security material should be read with code in hand; the details matter more than the checklist.
HTTPS and transport security
Study HTTPS content encryption, symmetric and asymmetric encryption, digital signatures and certificates, HTTP versus HTTPS, and SSL certificate principles. These concepts show up in interviews, but they also explain real deployment and debugging work.
Flash sales and high concurrency
Read about flash sale architecture and implementation, preventing inventory overselling, high concurrency, PHP concurrency approaches, Redis-backed flash sales, overselling under concurrency, demos, e-commerce flash sales, and architecture design examples. The strongest material connects business constraints with technical controls.
MySQL
A useful set covers the four transaction isolation levels, MySQL middleware, EXPLAIN execution plans, statistics and plan estimation, and classic interview questions. Query behavior and transaction semantics are part of backend design, not just database administration.
Redis
Read Redis interview questions, distributed clusters, Redis versus Memcache and Memcached, data types and application scenarios, and cluster principles, setup, and use. Cache design is often where performance and correctness meet.
Framework reading
Framework material can include Yii framework analysis, Laravel key technologies and architecture, Phalcon startup flow and MVC structure, container understanding, and a first look at Phalcon. Reading a framework's startup path is a practical way to study dependency injection, routing, and service containers.
Practical engineering extras
Two useful engineering topics are exporting million-row datasets by compressing multiple CSV files and implementing common sorting algorithms with animated diagrams. They are small enough to practice and concrete enough to reveal performance trade-offs.
A reading map is only useful if it leads to implementation. Pick one area, read two or three pieces, then rebuild the idea in a small script, a debug session, or a working prototype. That is where the material starts to stick.