Convert a Gettext PO Template file to a PO file and merge in existing translations if they are present. A translation memory (compendium) can also be used for fuzzy matching. This corresponds to a large extent with the program “msgmerge” from the gettext package.


This tool also works with translation formats other than Gettext PO, for example XLIFF.


pot2po [options] <pot> <po>


<pot> is a PO Template (POT) file or directory of POT files
<po> is a PO file or a directory of PO files


--version show program’s version number and exit
-h, --help show this help message and exit
--manpage output a manpage based on the help
 show progress as: dots, none, bar, names, verbose
 show errorlevel as: none, message, exception, traceback
-i INPUT, --input=INPUT
 read from INPUT in catkeys, lang, pot, ts, xlf, xliff formats
-x EXCLUDE, --exclude=EXCLUDE
 exclude names matching EXCLUDE from input paths
-o OUTPUT, --output=OUTPUT
 write to OUTPUT in catkeys, lang, po, pot, ts, xlf, xliff formats
-t TEMPLATE, --template=TEMPLATE
 read from TEMPLATE in catkeys, lang, po, pot, ts, xlf, xliff formats (old translations)
-S, --timestamp
 skip conversion if the output file has newer timestamp
-P, --pot output PO Templates (.pot) rather than PO files (.po)
--tm=TM The file to use as translation memory when fuzzy matching
 The minimum similarity for inclusion (default: 75%)
 Disable all fuzzy matching


pot2po -t zu-1.0.1 pot-2.0.2 zu-2.0.2

Here we are initialising the PO files in zu-2.0.2 based on the POT files in pot-2.0.2. We are using the old translations in zu-1.0.1 as templates so that we can reuse our existing translations in the new files.

pot2po can also be used to update against newer templates an existing translation file in a format different than Gettext PO, for example XLIFF:

pot2po -t af.xlf -i templates.xlf -o updated-af.xlf

If the POT files have undergone major reshuffling then you may want to use pomigrate2 which can now use pot2po as its merging backend. pomigrate2 will do its best to migrate your files to the correct locations before merging. It will also make use of a compendium if requested.

pot2po --tm=compendium.po --similarity=60 -t xh-old pot xh-new

With this update we are using compendium.po as a translations memory (you can make use of other files such as TMX, etc). We will accept any match that scores above 60%.


It helps to understand when and how pot2po will merge. The default is to follow msgmerge’s behaviour but we add some extra features with fuzzy matching:

  • If everything matches we carry that across
  • We can resurrect obsolete messages for reuse
  • Messages no longer used are made obsolete
  • If we cannot find a match we will first look through the current and obsolete messages and then through any global translation memory
  • Fuzzy matching makes use of the Levenshtein distance algorithm to detect the best matches


Fuzzy matches are usually of good quality. Installation of the python-Levenshtein package will speed up fuzzy matching. Without this a Python based matcher is used which is considerably slower.


  • pomerge and pot2po should probably become one.