PHP backend roadmap 2026

Learn variables, arrays, functions, strict comparisons, request methods and status codes. Keep secrets outside the public directory.

Build: Create an endpoint that returns a fixed JSON list of library books.

Review: Set the correct content type and explain the difference between 400, 401, 403 and 404.

Model books and loans separately. Understand primary keys, foreign keys and uniqueness before writing queries.

Build: Draw the schema and create realistic sample data, including an unavailable book.

Review: Explain what happens when a referenced book is deleted.

Use PDO prepared statements for values, validate on the server, and escape output for its destination.

Build: Add create, update and delete operations with field-level validation.

Review: Test missing fields, duplicate records, unexpected types and SQL-like text.

Learn password_hash, password_verify, secure session handling and CSRF protection for cookie-authenticated changes.

Build: Give members access to their own loans and librarians permission to manage books.

Review: Changing a record ID must not reveal or update another member’s loan.

Use transactions for related writes, structured logs and tests around failure paths. Do not expose stack traces publicly.

Build: Prevent two requests from checking out the same last copy.

Review: Demonstrate rollback when a multi-step operation fails.

Document endpoints, configuration and migrations. Use a supported PHP runtime and test backups by restoring them.

Build: Release the book-loan API with example requests and automated checks.

Review: Run setup on a fresh database; confirm secrets and personal data are absent from the repository.

Your portfolio outcome

Campus book-loan service with authorization, validation, pagination, concurrency handling and an API contract.