SantaDays

What It Is

SantaDays is secret letters to your friends. Each time a friend leaves a letter through your tree link, an envelope goes on your tree, and on the 25th of every month at midnight (Korea time) every letter opens at once. Until then even the tree's owner cannot see what was written or who wrote it.

The concept is "Santa's monthly room". Santa came last Christmas and never left: he lives in a small room with Rudolph and insists that every 25th is Christmas. The same room shows up every month with different props and light, and each month gets a name such as "The Original Christmas" or "Air-con Christmas". The brand line is "Christmas ended. Santa didn't leave."

The Problem

Even when you feel grateful, it is often hard to find a reason to say so. Outside birthdays and the end of the year, a short word of encouragement can feel awkward. On the receiving side, such words arrive one at a time and are soon forgotten.

SantaDays creates a monthly reason to leave a friend a few words and gives the receiver a day to open a month's worth of letters together. Senders only need to open the link, and receivers wait for opening day while envelopes go on the tree one by one.

Who It Is For

• Teens and people in their twenties: people who share how they feel with friends in group chats and on Instagram
• Groups that cheer each other on: school friends or clubs sharing their trees and leaving letters
• People who love waiting for a letter: people who want letters every month, not only on birthdays or at year's end

Core Flow

1. Make your tree: sign in with a Google account and create your own address.
2. Share it with friends: send your tree link, and friends leave a letter right away without signing in. Each person can send up to 5 letters a day.
3. Receive from the 26th to the 24th: every letter fills one drawer of the tree. On a day a letter arrives you get an email saying how many came, but the letters stay sealed.
4. Open on the 25th: at midnight on the 25th, Korea time, every letter opens at once, and only the tree's owner can read them. The first time, you open a gift box and page through the letters; after that they wait in your inbox. The opening also arrives by email.
5. Next month starts right away: from the 26th, next month's tree takes letters. There is no gap to wait through.

Key Features

• Your tree and share address: a personal page where friends come to leave letters. The tree has 24 drawers and a star on top.
• Letters without signing in: a writing screen a friend can use the moment they open the link.
• Received letters: the opened letters gathered as envelopes; pick two for a finale card you can share.
• Letter arrival email: once a day on days letters arrive, an email tells you how many came. What they say and who sent them open on the 25th.
• Letters by email: friends who have no tree yet can be sent a letter by email.
• Santa of the day: a daily post from Santa's room on Instagram and Threads.
• Five languages: Korean, English, Japanese, and Simplified and Traditional Chinese.

Product Decisions

• Filled by letters: the tree fills by the number of letters, not by date. When the 24 drawers are full, the 25th letter lights the star, and after that a +N appears next to it.
• Five a day: each person can send up to 5 letters a day, so no single friend takes over a tree.
• Contents only for the receiver: visitors see only the tree and how many letters have arrived. Letter contents and senders are never shown.
• Everyone opens at the same moment: the writing period and opening time are fixed to Korea time, so friends can share the excitement on the same day.
• No barrier for writers: friends leaving a letter never need to sign up. Tapping the link in KakaoTalk opens the writing card directly.
• Unkind words still fill a slot: abusive letters still count, but at opening the offending words are masked or the letter is hidden. That protects the tree owner while keeping the rule simple.
• Jokes stay in the pictures: the writing card and opened letters stay calm; the humor lives in the room pictures and a few lines.

Revenue Model

• One ad slot: an ad appears only in the window shown right after a letter is sent. The writing screen and opened letters carry no ads.
• Mr. Latte Membership: members read the letters that have arrived so far without waiting for the 25th. The 25th opening is the same for everyone.

Next Hypotheses

• How many friends' letters a single shared tree link leads to.
• Whether people who opened their letters on the 25th share next month's tree when it starts on the 26th.
• Whether the letter arrival email brings receivers back to their tree.
• Whether wanting to read letters before the 25th leads to membership sign-ups.