Encode::MIME::EncWords -- MIME 'B' and 'Q' header encoding (alternative)


    use Encode::MIME::EncWords;
    use Encode qw/encode decode/;
    # decode header:
    $utf8   = decode('MIME-EncWords', $header);
    # encode header with default charset, UTF-8:
    $header = encode('MIME-EncWords', $utf8);
    # encode header with another charset:
    Encode::MIME::EncWords->config(Charset => 'GB2312');
    $header = encode('MIME-EncWords', $utf8);


This module implements MIME header encoding described in RFC 2047. There are three variant encoding names and one shorthand special to a charset:

  Encoding name              Result of encode()     Comment
  MIME-EncWords              (auto-detect B or Q)
  MIME-EncWords-B            =?XXXX?B?...?=         Default is UTF-8.
  MIME-EncWords-Q            =?XXXX?Q?...?=                ,,
  MIME-EncWords-ISO_2022_JP  =?ISO-2022-JP?B?...?=

All encodings generate the same result by decode().


This module is intended to be an alternative of MIME-* encodings provided by Encode::MIME::Header core module. To find out how to use this module in detail, see Encode.

Module specific feature

config(KEY => VALUE, ...);

Class method. Set options by KEY => VALUE pairs. Following options are available.


[encode] Name of character set by which data elements will be converted. Default is "UTF-8". On MIME-EncWords-ISO_2022_JP it is fixed to "ISO-2022-JP".


[decode/encode] Try to detect 7-bit charset on unencoded portions. Default is "YES".


[encode] Name of the header field which will be considered on the first line of encoded result in its length. Default is undef.


[decode/encode] Specify mappings actually used for charset names. Default is "EXTENDED".


[encode] Maximum line length excluding newline. Default is 76.


[encode] Whether to do minimal encoding or not. Default is "YES".

For more details about options see MIME::EncWords.


  • The encoding modules for MIME header encoding are not the magic porridge pot to cook complex header fields properly.

    To decode address header fields (From:, To:, ...), at first parse mailbox-list; then decode each element by encoding module. To encode them, at first encode each element by encoding module; then construct mailbox-list of encoded elements. To construct or parse mailbox-list, some modules such as Mail::Address may be used.

  • Lines are delimited with LF ("\n"). RFC5322 states that lines in Internet messages are delimited with CRLF ("\r\n").


Please report bugs or buggy behaviors to developer.

CPAN Request Tracker:


Consult $VERSION variable.

This is experimental release. Features might be changed in the near future.

Development versions of this package may be found at


Encode, Encode::MIME::Header, MIME::EncWords.

RFC 2047 MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text.


Hatuka*nezumi - IKEDA Soji <hatuka(at)>


Copyright (C) 2011 Hatuka*nezumi - IKEDA Soji.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.