JSON to Elm Converter

Generate Elm type aliases from sample JSON when you want decoder-friendly frontend models that stay aligned with Elm application state.

How to use

  1. Paste a representative JSON payload that mirrors the API response your Elm frontend or package expects.
  2. Review the generated `type alias` blocks, nested alias names, and inferred list or Maybe fields.
  3. Copy the output into your Elm project and add decoders, modules, or domain-specific refinements where needed.

Benefits

  • Produces Elm-friendly model aliases that are easier to pair with decoders than hand-written records from scratch.
  • Keeps nested JSON payloads explicit in typed frontend model layers.
  • Helps Elm apps reduce drift between API samples and the data structures used in update/view logic.

Best use cases

  • Elm frontends that need typed records before writing decoders and API modules.
  • Single-page apps that want JSON-driven model scaffolding for ports, HTTP requests, or shared data.
  • Teams tightening payload contracts in Elm without manually authoring every nested alias first.

Elm alias tips

  • Generate aliases from representative samples so optional fields become `Maybe` only where the payload truly varies.
  • Pair the output with decoders right away so record shapes and parsing logic stay in sync.
  • Keep generated aliases in dedicated modules when multiple API endpoints share nested child records.

Sample JSON

{
  "id": 101,
  "name": "Ada Lovelace",
  "active": true,
  "roles": ["admin", "editor"],
  "profile": {
    "email": "ada@example.com",
    "score": 9.8
  }
}

Sample Elm output

type alias UserModel =
  {
    id : Int
,    name : String
,    active : Bool
,    roles : List String
}

FAQ

Why use the Elm route instead of TypeScript output?

Choose the Elm route when your destination code is Elm and you want Elm-specific record aliases and `Maybe`-aware field shapes rather than TypeScript interfaces.

Does the Elm route support nested arrays and child records?

Yes. Nested objects become additional type aliases, and repeated values are inferred into `List` fields based on the sample JSON payload.