CRUD · Create, Read, Update, Delete
/ krud /
CRUD is the four basic things almost every app does with its data: Create something new, Read it back, Update it, and Delete it. Add a note, look at it later, edit a typo, throw it away — that's all four, and you've been doing CRUD your whole life without the acronym.
It shows up everywhere because it maps cleanly onto the tools underneath. In a SQL database the four are INSERT, SELECT, UPDATE and DELETE; over HTTP in a REST API they're usually POST, GET, PUT/PATCH and DELETE. Same four ideas, just spoken in different dialects.
When someone says an app is 'just CRUD', they mean its job is mostly shuttling records in and out of a database with no fancy logic — which is most software, and nothing to be ashamed of.
POST /notes → Create GET /notes/42 → Read PUT /notes/42 → Update DELETE /notes/42 → Delete
The four CRUD operations as REST endpoints — one resource, four verbs.
Read is the only one of the four that doesn't change anything — handy to remember when you're worrying about what's safe to retry.