Explain the difference between nullable and non-nullable fields in GraphQL

beginner

Re-explain

In GraphQL, fields are nullable by default. The exclamation mark (!) makes a field non-nullable.

type User {
  id: ID!           # Required field
  name: String!     # Required field
  email: String     # Optional field (can be null)
  age: Int          # Optional field
  posts: [Post!]!   # Required array of required Posts
  tags: [String]    # Optional array of optional strings
}

Rewriting in plainer words…

This answer doesn't lend itself to a diagram - it reads best . No credits were charged.

Why there's no diagram: “”

The interactive diagram is below the answer - jump to diagram ↓ · Below it, the related concept . Jump to it ↓

The diagram below the answer is the concept . Jump to it ↓

Tailored explanation · switch back to · ·

What should the new diagram focus on?

How well did you know this?

AI:

Saved in this browser - sign in to keep your review list.

How should your speech become text?

Listening… your words appear above as you speak - tap Stop when you're done.

Recording · cr - tap Stop & transcribe when you're done.

Transcribing with AI…

Voice:

Keep going - a few more words and AI can grade it.

Interview lens

Likely follow-ups, what you can say, and the weak answers to avoid.

Want a quick review of the fundamentals? See the GraphQL cheatsheet.

← Back to all GraphQL questions

Pro · $10/mo

49 of 57 GraphQL answers are in Pro.

Full answers, code samples, and AI explanations that go simpler or deeper. Cancel anytime.

Full answers + code
AI explanations, simpler or deeper
1,000 AI credits / month
Cancel anytime

Get Pro → See plans & pricing →