Pretweet.co.uk removes phrases and major character names from tweets and Facebook posts.
Fans who want to share information about the film after they have seen it can check their tweets and posts using the automated form at Pretweet to avoid spoiling the film for others waiting in line.
Hamish Thompson at Houston PR said: "I’m old enough to remember the first Star Wars movie. Six months ahead of the premiere all we had to go on was a series of shots in the well-thumbed gatefold of the double album soundtrack in my local record shop. Now there are tweets and posts within seconds of any film screening.
"Pretweet.co.uk is essentially two bits of coconut tied together with string, but it should help a few fans to cleanse their tweets and avoid spoilers for others still queuing to see it."
Media attention around Star Wars: The Force Awakens has been huge, with many brands piggybacking on its popularity through social channels.