Unmarshalling a third-party response in Go means writing a struct that mirrors it exactly, and transcribing forty fields with the right tags is slow, error-prone work.
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JSON to Go Struct
Type / schema name
JSON
Free · API · MCPToolYour platform
Use JSON to Go Struct three ways
The free JSON to Go Struct on this page works in your browser. The same workflow is available via REST API for apps and via MCP for Cursor, Claude, and other agents — one API key, one plan, one quota. This tool is part of the developer-apis module under Developer Tools.
- Free in browserUse JSON to Go Struct here — no account required.
- REST APICall from your server with
X-Api-Key. - MCP for agentsConnect Cursor or Claude to ToolYour MCP with the same key.
- 1. Get an API keySign in and open Dashboard → API Keys (works for REST and MCP).
- 2. Call or connectUse the REST API from your server, or paste the MCP URL into your agent config.
- 3. Same qualityOutput matches the free web tool across all three surfaces.
What is JSON to Go Struct?
Unmarshalling a third-party response in Go means writing a struct that mirrors it exactly, and transcribing forty fields with the right tags is slow, error-prone work. This JSON to Go struct generator walks the sample and emits the root type plus nested struct definitions for embedded objects, with an exported field name and a json tag preserving the original key for each field.
Type mapping follows the obvious rules: strings become string, booleans become bool, whole numbers become int64, and numbers with a fractional part become float64. Arrays of objects generate a dedicated item struct. The limits are inherent to sample inference — a JSON number that happens to be whole in your example maps to int64 even when the API can send a decimal, nothing becomes a pointer, and no omitempty tags are added, so optional fields need your judgement. Run gofmt afterwards. For the same sample in a TypeScript project, use JSON to TypeScript.
Browser use is free and needs no signup. The same job runs over REST at POST https://api.toolyour.com/api/v1/developer-apis/json-to-go-struct and over MCP at https://api.toolyour.com/mcp — one API key, one shared monthly credit pool, 1 credit per successful call.
What are common questions about JSON to Go Struct?
Are json tags included?
Yes. Each field carries a json tag with the original key, so unmarshalling works even when Go naming differs from the wire format.
Does it add pointers or omitempty?
No. Optionality is not visible in a single sample, so add pointers or omitempty yourself where the API may omit or null a field.
How are numbers typed?
Whole numbers become int64 and fractional ones become float64. If the API can send either, widen the field to float64 or a custom type.
What are the key features of JSON to Go Struct?
Nested structs generated
Embedded objects and arrays of objects get their own named struct definitions.
Correct json tags
Original keys are preserved in tags while field names are exported Go identifiers.
Sensible numeric mapping
Integers and floats are distinguished from the sample rather than all becoming interface values.
How do you use JSON to Go Struct?
Paste a success response
Use a full example so optional-looking sections are actually present.
Name the root struct
Give it the name you want at the call site before copying.
Run gofmt and adjust
Format the output, then add pointers and omitempty where the API allows absence.
Go's unmarshalling rules that bite after generation
Two behaviours catch people who paste generated structs straight into a client. Zero values are ambiguous — a missing boolean and an explicit false both leave the field as false after unmarshalling, so if the distinction matters the field must become a pointer. The same applies to a numeric field where zero is a meaningful value.
Unknown fields are ignored silently — Go's decoder drops keys with no matching field by default, which means an API that adds a field, or a struct with a typo in a tag, fails invisibly. If you need to catch that, use a decoder with DisallowUnknownFields in tests. Neither behaviour is something a generator can decide for you, which is why both are left as deliberate edits.
The rest of the codegen cluster
The same JSON sample can seed clients in several languages, which is useful when one API is consumed by more than one service. Generate the Go client here, the TypeScript types with JSON to TypeScript, and the Python side with JSON to Python.
Keep one canonical sample in the repository so all three stay derived from the same evidence. Format it with JSON Formatter before committing so the fixture diffs cleanly when the API changes.
Which JSON / data codegen tools sit in this cluster?
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