Help Centre

Getting started

Peekjson is a diagnostic tool that tells you exactly where JSON parsing broke, and — when you fetch a URL — what the server actually sent. There are two modes:

Paste JSON — Paste a JSON blob directly into the text area. Parsing happens entirely in your browser. Nothing is sent to a server. The result shows the exact line and column of any error, with surrounding context and a plain-language explanation.
Fetch URL — Enter a URL pointing to a JSON API. The Peekjson server fetches it on your behalf and reports the status code, redirect chain, content-type, and whether the body parses as JSON. If the server returned an HTML error page with a JSON content-type header, you'll see both.

No account, no signup, and no cost. Open the App page to begin.

Frequently asked questions

1. What does "unexpected token" really mean?

When the JavaScript runtime (V8) cannot parse a string as JSON, it throws one of a handful of generic messages — the most common being "Unexpected token 'X' in JSON at position N". That message gives you a character offset but no line number, so on a 500-line blob you have to count characters manually.

Peekjson catches that same error and translates it into plain language. Instead of "unexpected token at position 4471" it shows you:

The exact line and column where parsing failed
The surrounding context with a visible marker
A human-readable description such as "Found an unexpected comma after the last array item" or "Expected a property name but found a closing brace"

2. Why can't my URL be fetched?

There are three common reasons a URL fetch fails:

The server is behind Cloudflare. A host that uses Cloudflare cannot be reached from the Peekjson server. This is a platform limitation of the Cloudflare Worker runtime — Cloudflare Workers cannot connect to Cloudflare-proxied origins by design. (See "Known limitations" below.)
The URL points to a private or blocked IP range. Peekjson blocks fetches to localhost, 10.x, 172.16-31.x, 192.168.x ranges, and private/internal addresses for security.
The server is down or unreachable. If the target server returns a non-2xx status, Peekjson reports the status code and body — you'll see what the server actually sent, even if it's an error page.

3. Where is my data processed? Is it private?

Paste JSON mode: Your pasted content never leaves your browser. The JSON.parse call runs in your browser's JavaScript engine. Nothing is sent to any server.

Fetch URL mode: The URL you enter is sent to the Peekjson server (a Cloudflare Worker) to perform the HTTP request. The response body is inspected and the structured result is returned to your browser. No content — URL or body — is stored, logged, or retained. Each request is stateless and independent.

See the Privacy Policy for full details.

4. Can I save my parse history?

Not yet. Peekjson does not have user accounts, so there is no way to persist or retrieve past parse results. Each session is stateless.

A saved history feature is planned for the Pro plan. It is not available today and cannot be purchased today. When it is built, it will let you review past parse results and share them with your team. See the Pricing page for details on what is planned.

5. Does Peekjson work with localhost or internal APIs?

No. For your security, the Fetch URL mode blocks connections to:

Private IP ranges (10.x.x.x, 172.16.x.x–172.31.x.x, 192.168.x.x)
Localhost / 127.0.0.1
Internal or link-local addresses

If you need to inspect a response from a local or internal API, fetch the response manually using your existing tools (curl, Postman, browser DevTools) and paste the body into Peekjson's Paste JSON mode.

6. The tool says "Cloudflare connection failure" — what can I do?

This happens when the URL you entered points to a server behind Cloudflare. Cloudflare Workers cannot connect to Cloudflare-proxied origins — it is a known platform limitation, not a bug in Peekjson.

Workaround: Retrieve the response body through another method (curl in your terminal, your browser's Network tab, or an API client like Postman) and then paste the raw JSON into Peekjson's Paste JSON mode. The paste mode gives you the same error analysis — line, column, and plain-language explanation — without needing a server-side fetch.

Known limitations

Peekjson is a focused, early-stage tool. The following limitations are known:

Cloudflare-proxied origins cannot be reached. The Peekjson server runs on Cloudflare Workers, which by design cannot connect to other Cloudflare-proxied hosts. Any URL behind Cloudflare will return a connection failure. The Paste JSON mode works as a workaround — see FAQ #6 above.

No user accounts or saved history. Every session is stateless. Planned Pro features (saved parse history, team workspaces, scheduled checks) do not exist yet and are not purchasable.
No email, alerts, or notifications. The tool has no way to contact you. No email sender is connected to this service. Plans that list "email alerts" describe features that are not yet built.
No payment processing. The pricing page shows a demo checkout form only. No money is collected and no plan can be purchased.
No following of redirects beyond the initial chain. Peekjson reports the redirect chain but does not follow redirects to new endpoints.
A single fetch per URL. Peekjson does not retry failed requests, does not cache responses, and does not poll or schedule re-checks.
No legal entity established. The operator of this service has not yet registered a legal entity, address, or jurisdiction. Terms, privacy, and billing commitments will be updated when that information is available.

Contact us

Email support is not yet available. This service does not have a contact mailbox or a registered operator. An email address will be established when a legal entity is registered and a support channel is operational.

If you have encountered a bug or have a feature request, you can record it with the site operator through the available business channels. Common questions are answered in the FAQs above.

Escalations — if you need something beyond what the FAQ covers (for example, a technical issue specific to your use case or a request for the operator), please note that these are currently handled directly by the site owner. There is no standard response time guarantee at this stage.