Free online JSON tools

Write, edit, format, minify, and validate JSON in a fast full-screen or embedded editor.

Format, prettify, and beautify messy JSON with configurable indentation and key sorting.

Compress JSON by removing whitespace to shrink payloads and speed up transfers.

Explore JSON with an interactive collapsible tree view.

Flatten nested JSON into a single-level object with dot or underscore keys.

Escape or unescape strings for code, logs, and API payloads.

Deep-merge two JSON objects — nested keys combine, arrays and scalars override.

Restore nested JSON from flat dot- or underscore-keyed objects.

Query JSON with dot paths and bracket indices — extract values at any key path.

Sort object keys alphabetically — recursively for stable, readable JSON.

Select or remove top-level keys from a JSON object — whitelist or blacklist fields.

Validate JSON instantly with precise, human-readable error messages and line numbers.

Fix invalid JSON: trailing commas, quotes, unquoted keys, and LLM markdown fences.

Validate and format JSON Lines — one JSON object per line.

Decode JWT header and payload — inspect claims without verifying signatures.

Analyze JSON structure — depth, key counts, types, and top-level fields at a glance.

Validate JSON5 with comments and unquoted keys, then convert to strict JSON.

Convert JSON arrays and nested objects into clean, flattened CSV ready for spreadsheets.

Turn CSV and spreadsheet data into structured JSON arrays.

Convert JSON to YAML for configs, Kubernetes, and CI pipelines.

Convert YAML configs and manifests into structured JSON.

Transform JSON objects into XML documents with a custom root element.

Parse XML documents into clean, structured JSON.

Encode text or JSON to Base64 and decode Base64 back to readable text.

Parse TOML config files into structured JSON for APIs and tooling.

Convert JSON objects to TOML for pyproject.toml, Cargo, and config files.

Convert a JSON array into newline-delimited JSON (JSONL / NDJSON) for logs and ML pipelines.

Combine JSON Lines into a single JSON array — one object per line to structured array.

Parse URL query strings into structured JSON objects.

Serialize JSON objects into URL-encoded query strings for APIs and links.

Percent-encode or decode text for URLs, query params, and API payloads.

Turn a JSON array of objects into CREATE TABLE and INSERT statements.

Convert a JSON array of objects into a GitHub-Flavored Markdown table.

Convert a JSON array of objects into a clean, escaped HTML table.

Generate RFC 6902 JSON Patch or RFC 7396 merge patch between two JSON documents.

Compare two or more JSON files and spot structural and value differences instantly.

Apply an RFC 6902 JSON Patch or RFC 7396 Merge Patch to a document and get the result.

Merge two edited JSON versions against a common base and resolve conflicts.

Infer a JSON Schema from example data in one click.

Validate JSON documents against a JSON Schema.

Generate TypeScript interfaces and types from any JSON sample.

Generate Python dict literals or dataclass-style structures from JSON samples.

Infer Go struct definitions with JSON field tags from example JSON.

Generate random nested JSON for tests, mocks, and schema prototyping.

Generate Java classes with Jackson annotations from JSON samples.

Generate C# classes with JsonProperty attributes from JSON examples.

Generate Zod schemas and inferred TypeScript types from JSON samples.

Generate Rust serde structs with rename attributes from JSON samples.

Generate Swift Codable structs with CodingKeys from JSON samples.

Generate Kotlin data classes with @SerializedName from JSON samples.

Convert JSON to a PHP array literal with short array syntax.

Convert JSON to a Ruby hash literal with the hash-rocket syntax.

Fix broken LLM JSON — fences, truncation, unquoted keys, and JS literals. Rule-based today.

Auto-fix JSON to match a schema — coerce types, drop extras, fill required fields.

Human-readable summary of JSON structure and field meanings from naming patterns.

Smart cleanup — remove nulls, empty strings, trim whitespace, drop empty objects.

Mask passwords, API keys, PII, and secrets before pasting JSON into an LLM.

Estimate the LLM token count of a JSON payload for context budgeting.