Glossary

This glossary provides short definitions of terms used throughout the book. The technology primers explain selected topics in more detail.

API: A defined way for software systems to interact.

Acceptance criteria: Observable conditions used to decide whether a change achieves its intended result.

Coding agent: Software that can inspect a project, explain it, run tools, and propose or make changes in response to instructions.

Authentication: Determining who is making a request.

Authorization: Determining whether someone may perform an action.

Backend: The shared part of Chahua that applies rules, works with stored data, and serves clients.

Branch: A movable name for one line of commits in a Git repository.

Business rules: Rules that define what actions an application permits and how it should behave.

Client: An application that communicates with a server on behalf of a person.

Commit: A recorded snapshot and explanation of a change in a Git repository.

Database: A system for storing and retrieving structured information.

Durable: Able to remain available after a request ends or a program restarts.

Diff: A comparison showing which lines or files were added, removed, or changed.

Frontend: The user-facing part of an application. In this book, it usually means the Chahua PWA.

Git: A version-control program used to record and combine changes to files.

GitHub: An online service for hosting Git repositories and collaborating on their contents.

HTTP: A request-and-response protocol commonly used for communication between web clients and servers.

Local state: A client’s current working view of information, which may be incomplete or briefly out of date.

Linter: A tool that reports suspicious code patterns or violations of project rules.

Object storage: A service for storing files and other large pieces of data as named objects.

PostgreSQL: The relational database system Chahua uses for its primary durable records.

PWA: Progressive Web App; a web application that can provide app-like features while running through web technologies.

Pull request: A proposal on a collaboration platform such as GitHub to review and combine one branch into another.

Remote: A named connection from one Git repository to another repository.

Repository: A project directory and the history Git maintains for it.

Staging area: The changes selected to become part of the next Git commit.

State: Information an application needs to remember while it operates.

Verification: Collecting evidence that a change satisfies its requirements and preserves relevant existing behavior.

WebSocket: A long-lived, two-way connection between a client and server.