Customized Exports

The Better BibTeX configuration pane can be found under the regular Zotero preferences pane, tab 'Better Bib(La)TeX'. Through the configuration pane of BBT you can customize the BibTeX file that will be exported:

• Automated background exports. Tick 'keep updated' during export, and that's that.
• Unicode conversion: the default is to retain unicode characters on export for BibLaTeX, and to convert to LaTeX commands (where possible) for BibTeX. You can specify whether you want to retain this default, or whether you want BBT to always export translating to LaTeX commands, or never to do this translation.
• Recursive collection export: when exporting a collection, recursive export will include all child collections. Note that this also sets Zotero to display collection contents recursively.
• Omit fields from export: Should you so wish, you can prevent fields of your choosing from being exported. In the configuration screen, add a comma-separated list of BibTeX fields you do not want to see in your export. The fields are case-sensitive, separated by a comma only, no spaces.
• Configurable citekey generator
• Push-and-Pull-Export: You can fetch your library as part of your build, using curl (for example by using the included zoterobib.yaml arara rule), or with a BiblaTeX remote statement like \addbibresource[location=remote]{http://localhost:23119/better-bibtex/collection?/0/8CV58ZVD.biblatex}. For Zotero standalone this is enabled by default; for Zotero embedded, this enables the embedded webserver.
• Add other custom BibLaTeX fields
• Scan your AUX files to get a list of references specifically for your article (and incidentally list missing references) by importing it.

BBT http export uses the general Zotero HTTP facility; please note that disabling this will disable ALL HTTP facilities in Zotero -- including the non-Firefox plugins provided by Zotero.

Add your own BibLaTeX fields

There are three alternative methods:

Square brackets []

You can add any field you like by using something like

bibtex[origdate=1856;origtitle=An Old Title]

in the extra field of your reference. This format is very rigid, it has no quoting syntax, so you can't have =, [, ] or ; in your key names or values.

JSON5

If you need more flexibility, you can use the JSON5 format instead:

bibtex{
  origdate: 1856,
  origtitle: "Can contain = and ';' just fine"
}

The marker for these fields can be either bibtex, biblatex or biblatexdata, but when importing BibTeX files with fields not supported by Zotero, the bibtex marker will be used. These fields are assumed to be valid LaTeX, and will be exported exactly as entered.

If you want to have them LaTeX encoded, add an asterisk (*) after the marker, so something like

bibtex*{
  origdate: 1856,
  origtitle: "Things like _ and $ will be escaped"
}

CSL fields

The final way to add fields is by using CSL fields in the format {:original-date: 1856}. These fields will not only be exported to Bib(La)TeX, but will also be picked up by the Zotero Bibliography manager, even though not all Zotero styles yet support this.

Common notes

If you add a field called referencetype using either of these methods, that value will be used as the reference type instead of the one usually inferred from the Zotero reference type. You can use this to create, for example, @customa{citekeyhere, ....} type references.

You can fix the citation key for a reference to a value of your choosing by adding the text bibtex: [your citekey] anywhere in the "extra" field of the reference.

Note that the default biblatex styles do not seem to support origdate; you can find possible solutions for this at Stack Exchange here and here.

You wanted customized...

You got customized. If you go into the Advanced preferences of BBT, find an edit field labeled Postscript, empty by default. In this, you can paste a JavaScript snippet which will be executed for each reference generated in the Bib(La)TeX exporter. In this code, you have access to the reference just before it will be written out and cached. The documentation-in-progress for the script environment can be found here; there are also examples on the wiki; feel free to add your own.