Inspect an API payload
Validate grammar and format JSON while preserving large numeric IDs; business-field validation remains separate.
Open JSON FormatterBUILT FOR EVERYDAY WORK
Developer Tools
Format and validate JSON, convert Unix timestamps, look up DNS records, and inspect SSL certificates, redirects, and public websites. Free online tools.
Website Inspector
Check public DNS, HTTPS, redirects, response headers, and basic page signals in one report.
DNS Lookup
Look up public A, AAAA, CNAME, MX, NS, and TXT records for a domain.
SSL Checker
Inspect a public HTTPS certificate's names, issuer, validity dates, and time until expiry.
Redirect Checker
Trace public HTTP and HTTPS redirects, with each response status, URL, and destination in order.
JSON Formatter
Format, validate, and explore JSON. Clear structure, precise data, all in your browser.
Unix Timestamp Converter
Convert Unix seconds or milliseconds to dates, and back.
6 useful tools. Free to use, with no signup.
Choose the right tool for your task
Choose the layer you are investigating. JSON checks payload syntax, timestamps identify instants, and public network checks describe DNS, certificates, or HTTP responses observed by our server.
Investigate a public website change
Start with a combined report, then use a focused DNS, SSL, or redirect tool for the affected layer.
Open Website InspectorRead a timestamp from a log
Select seconds or milliseconds explicitly and compare UTC with the browser’s local display.
Open Unix Timestamp ConverterMethods and worked examples
How to format and validate JSON
Work through invalid syntax, large numeric IDs, duplicate keys, and nested JSON strings without changing the data you meant to keep.
Read the guideCalendar days, date differences, and month-end arithmetic
Reproduce leap-year and month-end examples, choose inclusive or elapsed day counts, and understand why one calendar month is not always 30 days.
Read the guideHow to troubleshoot a DNS change
Check A, AAAA, CNAME, MX, NS, and TXT answers, distinguish a cached response from the intended record, and separate DNS problems from HTTPS or redirect problems.
Read the guideHow to check the certificate a website actually serves
Inspect certificate dates and hostnames, diagnose a renewal that did not reach the endpoint, and understand the limits of an SSL expiry check.
Read the guideHow to diagnose redirect chains without losing the query string
Follow a worked HTTP-to-HTTPS chain, distinguish temporary and permanent redirects, and check paths, campaign parameters, and loops.
Read the guide