API Payload Debugger

About

Detailed Description

API Payload Debugger is an all-in-one JSON toolkit built for developers, QA engineers, testers, and API teams.

Repair malformed JSON, compare payloads, generate TypeScript interfaces, decode JWTs, query with JSONPath, and convert formats — all directly inside your browser with zero data collection and zero external servers.

Everything runs locally.

No analytics.
No tracking.
No background requests.
No permissions required.

Features
Repair & Format JSON

Fix malformed JSON instantly:

Trailing commas
Single quotes
Unquoted keys
Smart quotes
JavaScript comments
Invalid escape characters

Then:

Format JSON
Minify JSON
Sort object keys
Escape/unescape stringified payloads
Analyze Payloads

Inspect large responses quickly:

Detect inconsistent field types
Find oversized payload paths
Measure payload size (Bytes / KB / MB)

Perfect for debugging API responses and optimizing contracts.

JSONPath Query Support

Run powerful JSONPath queries:

$.users[*].email
$..id
Recursive selectors
Filters and slices

Copy matched paths instantly.

Mask Sensitive Data

Sanitize payloads before sharing:

Mask keys by name
Regex-based masking
Replace values with [masked]
Remove sensitive fields entirely

Useful for logs, tickets, bug reports, and screenshots.

Structural JSON Diff

Compare two payloads side-by-side:

Added fields
Removed fields
Changed values
Type mismatches

Built for API debugging and regression analysis.

Generate Developer Types

Generate code from sample JSON:

TypeScript interfaces
Zod schemas
JSON Schema (Draft-07)

Supports nested arrays, optional fields, and unions.

Convert Formats

Convert JSON into:

YAML
CSV
URL query strings

Fast, clean, and copy-ready.

Interactive Object Paths

Explore payload structures visually.
Copy usable access paths like:

users[0].profile.name

Great for debugging and testing.

JWT Decoder

Decode JWT tokens locally:

Header
Payload
Expiration
Issued-at timestamps
Valid/expired indicators

Supports tokens with or without Bearer.

NDJSON Support

Automatically detects and processes newline-delimited JSON (NDJSON).

Privacy First

This extension is fully local-first.

Permissions
No permissions required
No host permissions
No optional permissions
Data Collection
No analytics
No telemetry
No tracking
No data collection
Remote Code

No remote scripts, CDN imports, or external runtime code.

The extension operates entirely inside the browser.

Built For
Backend Developers
Frontend Developers
QA Engineers
SRE / DevOps Teams
API Testers
Security Researchers
Tech Stack

Built with:

React
TypeScript
Vite
jsonrepair
One-Line Promo Tagline

Everything you do to JSON — locally, privately, in one tab.

Privacy Practices (Important for Google Submission)
Single Purpose Description

Provides local JSON debugging, formatting, repair, conversion, comparison, and schema generation tools for developers.

Remote Code Justification

This extension does not use remote code. All scripts, assets, and application logic are bundled locally within the extension package.

Data Usage Certification

This extension:

Does not collect user data
Does not transmit data externally
Does not sell or share data
Does not use analytics or tracking
Release Notes (What's New)

Initial release featuring:

JSON Repair
JSON Formatter
JSONPath Query
Payload Diff
Type Generation
JWT Decoder
Format Conversion
Sensitive Data Masking