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Development, debugging and network detection tools

Compare text, test regular expressions, parse URLs, User-Agent strings and Cron schedules, inspect network and DNS information, look up commands, run short code snippets or view SQLite files read-only.

Select tool

  • DNS record query

    Query public records such as A, AAAA, MX, TXT, etc., and display TTL and parsing status.

  • Mail DNS check

    View DKIM public records for MX, SPF, DMARC and the specified selector.

  • Reverse DNS lookup

    Convert IPv4 or IPv6 to a reverse lookup name and view public PTR records.

  • CAA Record Check

    Viewing the certificate issuance authority record for the current name does not replace the complete issuance policy check.

  • DNSSEC status check

    Look at the DNS response for verification flags; unsigned does not mean verification failed.

  • IP and connection detection

    Check the current exit IP, region and connection time, and you can also query the ASN, network organization and city information.

  • URL parsing and parameter editing

    Split the complete link into protocols, domain names, ports, paths and fragments. Query parameters are edited individually in order of appearance, making it easy to troubleshoot duplicate keys, null values, and encoding issues.

  • Cron expression parsing

    The five segments of Cron represent minutes, hours, days, months, and weeks in sequence. First use Chinese instructions to understand the cycle, and then check the running time with time zone offset to avoid tasks being executed at the wrong time.

  • User-Agent parsing

    Parses browser, operating system, engine, device, and CPU clues from User-Agent strings. Displays parsing results by category, supports examples and manual reading of the current browser UA, and does not perform device fingerprint detection.

  • Text difference comparison

    Compare two pieces of text locally, distinguish additions and deletions, and retain differences in spaces, tabs, and line breaks. Supports swapping sides, blank examples, and variation quantity summaries without uploading or creating sharing links.

  • Regular expression testing

    Run browser JavaScript regex in isolation and view matching text, UTF-16 positions, capturing groups, and named groups. Provides flags switches and examples, stops with timeout, and displays up to 500 matches.

  • Quick check of commonly used Linux commands

    Search for independently written descriptions of common commands, read-only examples, and easily overlooked limitations.

  • Commonly used regular templates

    Check out common JavaScript regular rules, matching examples, and validation boundaries, and copy and test them yourself.

  • Local MicroPython interpreter

    Execute the short Python example in an isolated browser environment and see the printed results.

  • Native Lua interpreter

    Run a short Lua example on a separate background thread and see the printed results or errors.

  • SQLite read-only viewer

    Open a local SQLite file, select a common data table, and view fields and records in pages.

How to choose

Check the modification results
Text comparison displays new, deleted, and retained content by line or word; swapping left and right input can change the direction of comparison. Whitespace and line breaks can also make a difference.
Debug matching rules
The regex tool uses the browser's JavaScript engine to display matching and capturing groups. The syntax and behavior of engines such as PCRE, Python, and Java may differ.
Check with a small sample first
Validate with representative normal input and mismatched input. The success of a single example does not mean that the expression can handle all production data.