API Response Visualizer

Paste JSON from APIs: collapsible tree view, TypeScript interfaces, and optional Zod schema generation.

JSON response

All parsing runs in your browser — nothing is uploaded.

JSON tree

id:"usr_01"(string)

name:"Farhan"(string)

age:25(number)

active:true(boolean)

0:"admin"(string)

1:"editor"(string)

lastSeen:"2025-05-06T12:00:00Z"(string)

0:9.5(number)

1:8.2(number)

2:10(number)

Generated code

/** Generated from JSON sample — verify optional fields and unions for production. */
export interface ApiresponseMeta {
  lastSeen: string;
  scores: number[];
}

export interface Apiresponse {
  id: string;
  name: string;
  age: number;
  active: boolean;
  roles: string[];
  meta: ApiresponseMeta;
}

14 lines

API Response Visualizer guide

Developer Tool

Modern APIs return JSON: nested objects, arrays of mixed records, nullable fields, and timestamps as strings. Reading that in a terminal or a minified log line is painful when you only need to answer simple questions—what shape did this endpoint return, which keys can be null, and how would you type this in TypeScript? API response visualization turns opaque text into something your eyes already know how to parse: an outline with indentation, expansion on demand, and labels that remind you whether a value is a string, number, boolean, array, or nested object. This tool is aimed at the same workflow as the Network panel in browser DevTools, but strips away unrelated tabs so you can paste a payload from curl, Postman, or a server log and focus purely on structure. Because everything runs in your browser, you can safely inspect proprietary responses without uploading them to a third-party formatter.

What is API response visualization?

Visualization here means turning JSON text into a navigable tree. Each object becomes a branch you can fold closed when you do not care about its internals; each array exposes indexed children so you can spot length and element shape quickly. That interaction matters when responses are large—expanding only the branches you need reduces noise compared to scrolling a thousand-line pretty-print. The viewer also prints inferred types next to scalar values so you can distinguish `"42"` as a string from `42` as a number at a glance.

Alongside the tree, generated TypeScript interfaces give you a starting point for client code: interfaces follow the sample payload you pasted, so union types appear when the same field differs between array elements. A companion Zod schema string lets you validate responses at runtime if your stack already uses Zod—handy for route handlers and integration tests. Neither replaces automated OpenAPI clients when your API publishes a spec, but both bridge the gap when you only have example JSON from production.

How to use this tool

Paste JSON into the textarea—typically copied from DevTools, Logflare, or `curl -s` output—and click Visualize JSON. The tree opens with several levels expanded by default; use Expand all or Collapse all if you want a bird’s-eye view or a minimal outline. Format JSON re-indents with two spaces; Minify removes whitespace when you need to compare payloads by character count or paste into a narrow column. Copy JSON sends the raw textarea contents to your clipboard; individual nodes also expose a copy control so you can grab a subtree without selecting text manually.

The right column shows generated TypeScript and an optional Zod module. Copy TS into your codebase and tighten unions or mark optional fields after you confirm them against more samples. Copy Zod only if you already depend on `zod` in your project—the snippet assumes `import { z } from "zod"`. For very large responses, expect slower rendering; trim irrelevant arrays or paginate at the source when profiling.

Benefits for developers and JSON debugging tips

Frontend engineers use tools like this when backend contracts lag behind code: paste the latest staging response and align your types before opening a pull request. Backend engineers validate that error payloads match what mobile clients expect—especially useful when multiple services wrap errors differently. Support engineers can anonymize customer JSON locally, explore it here, and paste redacted screenshots into tickets without shipping data to external servers.

When debugging JSON, start by collapsing everything except the path that misbehaves—often a single array element differs from the rest. Watch for numbers serialized as strings when comparing to TypeScript types. Remember that JSON has no `undefined`; missing keys and explicit `null` mean different things for optional fields. Finally, regenerate interfaces whenever the API version bumps—sample-driven typing is only as accurate as the payloads you feed it.

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