Debug API responses
Paste raw JSON from an API response, format it, validate it and inspect nested objects or arrays before using it in your code.
JSON tools
Free online JSON tools for developers working with APIs, authentication tokens and AI workflows
Format, validate, minify and inspect JSON directly in your browser. Use these tools to debug API responses, decode JWT payloads, encode or decode related data and estimate LLM token usage for JSON-based prompts and workflows.
Essential JSON tools
Start with these tools when working with JSON payloads, API responses, authentication tokens or structured content for AI models.
JSON Formatter and Validator
Format, validate and minify raw JSON directly in your browser. Useful for API responses, configuration files and debugging.
JWT Decoder
Decode JSON Web Tokens and inspect header, payload, claims, expiration time and signature without sending data to a server.
LLM Token Estimator
Estimate token usage and approximate cost for JSON payloads, prompts and AI workflows.
Related API and encoding tools
JSON often travels through tokens, encoded strings, URLs and timestamps. These related tools help you inspect the full data flow.
Base64 Encoder and Decoder
Encode text to Base64 or decode Base64 strings used in API payloads and integrations.
URL Encoder and Decoder
Encode and decode JSON values passed through query strings, redirect URLs or callback URLs.
Unix Timestamp Converter
Convert timestamp fields such as exp, iat and nbf into readable dates.
Common use cases
Inspect authentication payloads
Decode JWTs, read token claims and convert timestamp fields to understand expiration and authorization data.
Prepare JSON for AI workflows
Estimate how many tokens a JSON payload or structured prompt may use before sending it to an LLM.
Inspect webhook payloads
Format and validate JSON payloads received from webhooks to quickly understand their structure and content.
Browser-based and privacy-friendly
These tools are designed for quick checks while developing, debugging or testing. JSON formatting, JWT decoding, Base64 conversion and token estimation run locally in your browser, so sensitive payloads are not sent to external servers.