Glossary
The jargon you’ll meet in the doctrine — explained in plain terms, with a real-life analogy.
API
An agreed way for two programs to talk to each other — one asks, the other answers in a set format.
Like a service window at an office: you submit your request the right way and get an answer, without going into the back room.
Backup
A copy of your data saved earlier, which you return to when something goes wrong.
Like taking a photo of a shelf before rearranging the books — if you slip up, you can put everything back.
Branch
A separate working version of the project where you change something on the side, without touching what already works.
Like a “to think over” copy of a document — you play with it freely while the original waits untouched.
Cache
A temporarily remembered result, so you don’t compute the same thing again on every request.
Like jotting the receipt total on a note instead of re-adding the whole basket every time.
Commit
A saved, labelled point in the project’s history — a confirmation of a specific batch of changes.
Like a save point in a game: at any moment you can return exactly to that spot.
Deploy
Releasing a new version of the app “live”, where real people use it.
Like a play’s premiere: rehearsals are over, the curtain goes up and the audience is already watching.
Docker / container
Packaging an app together with everything it needs, so it runs the same on every computer.
Like a takeaway meal in a box with a full set of cutlery — you unpack it anywhere and it’s ready, nothing missing.
Dry-run
Running a script “dry”: it shows what it would do, but changes nothing for real.
Like trying on clothes before the till — you see the effect before paying for anything.
Environment (dev / prod)
Separate places where the app runs: “dev” for safe tests, “prod” for real users.
Like a test kitchen and a dining room in a restaurant — you experiment in the back and serve only the tried dish.
Feature flag
An internal switch that turns a new feature on for some people, or off, without changing the code.
Like a dimmer switch: you let a novelty in gradually, and if it glares, you dim it in one move.
Framework
A ready-made skeleton with the basic parts of an app, which you build on instead of starting from scratch.
Like a prefab house in a raw state — the walls and wiring are there, you fit out the interior your way.
GDPR
EU rules on protecting personal data — what you may do with it, how to secure it and when you need consent.
Like the rules for keeping someone else’s documents in a safe: you don’t show them to just anyone and you ask before you use them.
hreflang
A tag that tells a search engine which language a page is in and where its versions in other languages are.
Like flags next to the menu in a tourist restaurant — you see at once which card is in English and which in Polish.
Idempotency
A property of an operation you can run many times with always the same result, without duplication.
Like a light switch marked “ON”: pressed once or five times, the light simply stays on.
Index (database)
A directory in the database that makes searching lightning-fast, instead of scanning everything one by one.
Like the index at the back of a book — you look under a term instead of reading 400 pages for one sentence.
Migration (database)
A controlled change to the database layout — adding a column, a table, or moving data — done step by step.
Like a flat renovation to plan: you move walls in a set order so nothing collapses.
N+1
A performance bug where the app queries the database 200 times instead of once, because it asks about each item separately.
Like phoning the warehouse separately about every product, instead of asking once for the whole list.
Repository (repo)
A store of the whole project’s code together with its full history of changes — who changed what and when.
Like a binder of document versions, where every edit is labelled and can be restored.
Rollback
Returning to the previous, working version when a new one has caused trouble.
Like undoing a move in a game or an entry in a document with “undo” — you go back to the state before the slip.
Slug
A readable, short part of a page’s address that describes its content in words instead of a cryptic number.
Like a clear label on a folder, “lease-agreement”, instead of “document-42” — you know at once what’s inside.