Debugging JSON and JWTs without uploading your inputs: Payload Haven

Kris Kohlstedt — Sun, 11 Oct 2026 19:56:55 +0000

I built Payload Haven, a free collection of developer utilities that process tool inputs in your browser. No account or upload is required to use the tools.

Here are three workflows you can try with sample data.

1. Compare JSON values instead of formatting

Suppose an API changes from:

{"status":"pending","user":{"name":"Ada"},"tags":["api"]}

to:

{"tags":["api","private"],"user":{"name":"Ada"},"status":"complete"}

The JSON comparison tool ignores object key order and reports changed paths. In this example, /status changes and /tags/1 is added. Arrays are compared by position, so reordering them can produce several changes. Paths use JSON Pointer escaping to distinguish keys that contain slashes.

2. Inspect a JWT without confusing decoding with verification

The JWT decoder displays the header, payload, and timestamp claims. Decoding does not verify the signature or establish that the claims are trustworthy. Your application still needs to verify the signature and validate the issuer, audience, expiry, and other requirements for its use case. The sample token is deliberately not a credential.

3. Encode Unicode text correctly

The Base64 tool converts text to UTF-8 bytes before encoding, so inputs such as café 👋 round-trip correctly. It also supports URL-safe Base64. Base64 is encoding, not encryption. For individual query parameter values, use the separate URL encoder instead.

What else is included?

JSON formatting, validation, minification, and syntax error locations
URL encoding and decoding
Unix timestamp conversion with explicit time zones
Random v4 UUID generation, including batches
JSON string escaping and unescaping
Result downloads and settings-only sharing links

Tool inputs and results are not uploaded for processing. The site has a separate analytics choice described on its privacy page; browser-local processing does not mean that loading a website makes no network requests.

One limitation: the JSON tools use JavaScript numbers, which can round very large integers or high precision decimals. Preserve the original input when exact numeric representation matters.

I would appreciate specific feedback: which workflow would you bookmark, and what currently makes it awkward to use?

Disclosure: I used AI assistance to build the site and draft this post.

DEV Community: Kris Kohlstedt

Debugging JSON and JWTs without uploading your inputs: Payload Haven

1. Compare JSON values instead of formatting

2. Inspect a JWT without confusing decoding with verification

3. Encode Unicode text correctly

What else is included?