Help Centre

Getting started, common questions, and known limitations — everything you need to use Parseproof effectively.

Getting started

Parseproof has two modes. There is no account, no signup, and no data collection.

  1. Open the tool at /app.
  2. Choose a mode: click the “Paste JSON” tab to validate text you already have, or “Fetch URL” to inspect a live API response.
  3. Paste mode: drop your JSON into the text area and press Ctrl+Enter (or click the button). Parsing happens in your browser — nothing is sent to any server.
  4. Fetch mode: enter a URL and click the button. The tool fetches the URL server-side and returns the HTTP status, response headers, and full body. The URL is not stored or logged.
  5. Read the output: if the JSON is valid, you see it pretty-printed. If it is not, Parseproof marks the exact line and column with a caret (^) and explains what went wrong in plain language.

Frequently asked questions

Real questions from developers using Parseproof.

I see “unexpected token at position 4471” from my API client. What does Parseproof tell me instead?

Parseproof translates that opaque byte offset into a line and column number, draws a caret (^) diagram pointing at the exact problem character, and explains what was expected there in plain language. For example, instead of “unexpected token at position 42” you might see:

Line 3, column 14
{"name": "Alice",, "age": 30}
                   ^
Expected a property name (string), but found a comma.
Parseproof says my API returned HTML. Why?

A surprisingly common problem: many servers return an HTML error page (a 404, 503, or 500 with human-readable HTML) but send a 200 OK status and label it Content-Type: application/json. Parseproof shows you the actual response headers including the real Content-Type, so you can see the mismatch. If the body starts with <!DOCTYPE html> but the Content-Type says JSON, Parseproof flags that discrepancy.

Can Parseproof reach a Cloudflare-hosted API?

No. Parseproof fetches URLs through a Cloudflare Worker, and Cloudflare blocks Worker-to-Worker requests. If the target API is behind Cloudflare, you will see a “This host is behind Cloudflare and cannot be reached from this tool” message rather than a misleading connection error. In this case, try pasting the raw JSON response body directly instead of fetching via URL.

Is my pasted JSON sent to your servers?

No. When you paste JSON text, parsing happens entirely in your browser using JavaScript’s built-in JSON.parse(). Your content never leaves your machine. URL fetches are proxied through the Parseproof Worker, but the URL and response are not stored, logged, or written to any persistent storage. See the Privacy Policy for full details.

The URL fetch returned a non-2xx status — what does that mean?

If the server responds with a status outside the 200-299 range (e.g. 301, 400, 403, 500), Parseproof reports the actual status code and marks every derived verdict as not established. It will not attempt to parse an error page as valid JSON or report false positives about your JSON structure. Check the status code and response body — the problem is likely at the server, not in your JSON.

Parseproof says my JSON is valid, but my API still doesn’t work. What now?

Parseproof checks JSON syntax only. It does not validate schema (whether the right fields are present with the right types), check authentication headers, test business logic, or verify that your request matches the API’s contract. If the JSON parses correctly, the issue is elsewhere in your integration — check endpoint paths, HTTP method, authentication, and the expected request format in the API documentation.


Known limitations

These are honest descriptions of what Parseproof does not yet do, or cannot do because of the infrastructure it runs on.


Contact us

Support is not yet reachable by email or phone. The operator of Parseproof has not registered a company, established a contact address, or connected a mailbox to this domain.

This is a known gap. A contact method is a documented requirement in the fleet’s needs tracking, and the operator is aware that it needs to be set up. Until then, please refer to this Help Centre for self-service answers. If you need something that is not covered here, revisit this page in the future when a contact route has been established.
Reporting a security issue or abuse: Same limitation applies — there is no security contact address yet. This is part of the same outstanding requirement.