Problem:
I would like to send out physical invitation letters (not the actual questionnaire) to some people with a link to a site containing a textbox ("type your token here"), where the respondent yhen can type his/hers token and be forwarded to his/hers relevant survey. Is that possible?

If the "&sid" is removed from the surveylink, this would be possible quite easily by entering the token in the form which completes the link:
index.php?lang=en&sid=xxxxx&token=xxxxxxxxxxxxxx

however, it's not possible to remove the "&sid" (or "lang=xx" for that matter).

Kind regards, toby

I don't think that LimeSurvey will do this on its own, but you can do it by using a URL shortening service (goo.gl, bit.ly, snurl.com, etc).

Create a shortened URL for each survey, and then send the shortened link and token to your survey participants. Be sure that the shortened URL includes the sid and language values.

Any of the shortening services will work, but snurl.com will allow you create custom text for your links (such as snurl.com/toby-survey1).

Just a short note: If you are not using a multilingual survey you don't need to pass the language information. Even at multilanguage surveys this is not always necessary because Limesurvey will switch to the base language automatically.