This unique delivery service allows customers to send minuscule letters which have to be read with a magnifying glass.
Since it opened, The World’s Smallest Post Service – or WSPS – has sent tiny packages and messages all over the world.
WSPS Founder Lea Redmond, 33, said: “Every year we send hundreds of tiny Christmas cards.
“We have probably sent more love letters than anything else, but we also send birthday cards, Mother’s Day cards, and even letters to children from the Tooth Fairy.
Ms Redmond sends an average of 500 letters a month and expects this figure to double over the Christmas period.
She said: “In this era of tweets and text messages, we long for authentic connections. A piece of miniature mail is so special and wonderfully strange that it invites the letter-writer to be especially thoughtful.
“Whatever the occasion, the notes are heartfelt, clever, silly, and serious. They are diverse and wonderful, just like people who send them.”
The World’s Smallest Post Service was started by Ms Redmond as an offshoot of her company Leafcutter Designs.
Ms Redmond said: “I sewed myself a postal uniform and set up my mini post office in cafes and shops. I had a tiny wooden doll’s desk which I used to transcribe customers’ letters into tiny writing.
“In the early days of the project I hand-wrote the letters with a fine tipped pen. I have very steady hands. Today, the letters are printed in a minuscule font that makes it more fun to read with a magnifying glass.”
The mini envelopes are just one inch wide and decorated with a small wax seal stamped with the recipient’s initials.
Since launching the service in 2008 Ms Redmond, of Berkeley, California, has branched out and started producing tiny packages containing whimsical gifts.
She said: “Each one has a different small object and message inside. For example, you might lift the lid off the box to find a little note that says ‘You are as cute as a…’, and hiding within you would find a button.”
Ms Redmond thinks the growing popularity of the World’s Smallest Post Service is due to the fact that sending a physical letter is now a novelty.
She said: “These tiny letters and tiny packages are magical. The radical scale shift stops us in our daily tracks and invites us to be playful and imaginative.”