Punycode Encoder & Decoder

Punycode Encoding & Decoding: Core Features and Principles

When you need to register a domain containing non-ASCII characters, such as "中文.中国" (Chinese.China), browsers and DNS systems cannot recognize it directly. This tool solves that core pain point. Punycode is an encoding scheme that converts Unicode strings (like non-English domains) into a subset of ASCII characters, allowing Internationalized Domain Names (IDNs) to function within the existing DNS architecture. The tool converts an input like "例子.中国" (example.china) into an ASCII-formatted Punycode string like "xn--fsq.xn--fiqs8s", and vice versa.

Why Choose Our Punycode Converter?

• Accurate Two-Way Conversion: Strictly follows the RFC 3492 standard, ensuring the accuracy and reversibility of both encoding and decoding.
• Automatic Detection: No need to manually select a mode. The tool automatically determines whether to encode or decode based on your input.
• Client-Side Processing: All conversions are performed locally in your browser without any network requests, ensuring the privacy and security of your input.

How to Use

1. Paste or type the string you want to process (e.g., an IDN or a Punycode string) into the input box.
2. Click the "Convert" button. The tool will automatically detect the format and perform the encoding or decoding.
3. View the result in the output box and copy it for direct use.

Frequently Asked Questions (FAQ)

Q: Do Punycode-encoded strings always start with "xn--"?
Yes. According to the standard, all non-ASCII domain parts encoded with Punycode use the ACE (ASCII-Compatible Encoding) prefix "xn--". This is the key identifier of a Punycode string.

Q: Can the tool process a full URL, such as "https://中文.中国/path"?
No. This tool only processes the domain name itself. For a complete URL, you should extract only the domain part (e.g., "中文.中国") for conversion. The protocol (http/https) and the path (/path) should not be encoded.

Important Notes

When using this tool, please ensure your input consists only of domain labels (e.g., "中文", "中国"). Do not include prefixes like "http://" or "www.", nor trailing slashes. There are length limits for encoded results; excessively long domains may fail to convert. When decoding, ensure the input Punycode string is correctly formatted and complete. This tool does not store or upload any of your input data.

Technical Notes & Best Practices

For developers and domain administrators, using this tool to verify IDNs before handling them in applications or configuration files can prevent compatibility issues. A typical use case: when deploying a domain like "企业.公司" (enterprise.company) to a legacy system that only supports ASCII, first encode it to "xn--fct102k.xn--55qx5d" before configuring. Remember, Punycode encoding only alters the "label" parts of the domain. Subdomains and top-level domains (like .com, .net) remain unchanged if they are already in English. Using the Punycode format uniformly when dealing with mail servers (SMTP) or database indexing ensures consistency.