Open When Letters: How to Write a Series of Letters

The idea behind open when letters

Each envelope carries a label saying when to open it: "open when you're sad," "when you start a new job," "when you feel alone," "when you miss me." The recipient keeps the stack and picks one at the right moment. What makes them work is precision: you are not writing a general letter, you are writing to someone in a particular situation.

The format suits couples separated by distance, a child leaving for college abroad, a friend who is moving away, someone going through a hard stretch. In every case, the series says one simple thing: I thought of you before you needed it.

When you're sad or nothing is going right
When you start a new job or a new chapter
When you doubt yourself before an exam or an interview
When you miss me
On the first day of school, the day you pass your driving test, the day you leave

A letter for every birthday, from birth to 18

This is the most touching version: a letter for every birthday, from the day your child is born until they turn 18. Eighteen short notes, sealed in advance, that tell a whole childhood. The day they open one, they read what you thought of them at that age, what made you laugh, what you hoped for.

There are two ways to do it. You can write each year around the birthday, to keep the freshness of the moment as it is lived. Or you can write ahead, projecting forward: a letter for their tenth birthday, another for starting middle school. Often the best approach is a mix, with a few letters written in advance for the big milestones and a spontaneous note each year. Each letter only needs ten lines: the age they are, one specific memory, a detail of the era such as the price of a coffee, and a wish.

Letters to open each year: an appointment that repeats

Letters to open each year work like a ritual. A couple can write one for every anniversary of the day they met, a family for each New Year's Eve, a parent for the start of every school year. You open the letter for the year, read it aloud or in silence, and then write the ones for the years ahead in response.

Their value comes from repetition: reread ten years later, they show what changed. A single letter keeps a moment. A series keeps a trajectory.

A countdown before a big day

A series can also lead up to a date instead of starting from one. Before a wedding, a big departure, or a birth, you prepare one capsule per day or per week, each opening a little closer to the day itself. The weeks of waiting become a path you walk together.

Before a deployment, a trip, or a year abroad, a parent can leave one message a week. Before a birth, grandparents or soon-to-be parents can write to the baby, one note for each remaining month, to be discovered together when the time comes.

How to plan a series of letters

Before writing the first line, make three choices: theme, rhythm, and format. The theme says what the series is about (a childhood, a departure, a couple). The rhythm says how often it opens: every day, every week, every year. The format says what each capsule contains, because a series is stronger when the media vary.

A rhythm that is too dense wears people out, one that is too spread out makes them forget the series. For a countdown, one a day or a week. For a childhood, one a year. For letters of support, write fewer, but choose them well.

Text for words that deserve to be weighed, reread, and kept
A photo to hold a moment or a place: the house, the garden, the street
A video to show a gesture, a fit of laughter, a birthday
A voice message for the voice itself: parents, grandparents, friends
The prices of the day, the song of the moment, what everyone was talking about that year

Building a time capsule series with Future

On paper, a series of letters sits in a drawer and depends on whoever keeps it. With Future, you create capsules, meaning texts, photos, videos, or voice messages sealed today that only open at the moment you choose. Until then, the recipient knows a capsule is waiting but cannot see what is inside. You can delete it while it is sealed.

For a time capsule series, Future has a dedicated mode: each capsule opens a set number of days after the previous one. You can also set a capsule to open on a specific date or at an age, such as an 18th birthday. One honest note: Future's series follow time, not emotions. There is no letter that opens "when you're sad" at the moment the sadness arrives. To recreate the spirit of open when letters, you schedule them at dates that match the moments: the first day of school, the first day of work, a birthday, the day of the departure. And for days when someone misses you, a series spaced a few days or weeks apart does the job nicely.

For a child who isn't here yet, and how to start

A series also works for a child who has not been born yet or is too young for a phone. You create a future member profile: the day they join Future, they enter the invitation code you give them and find everything that was waiting. Capsules are private, exchanged only between accepted members, with no public feed and no ads, and hosted in the European Union.

Future is free on iOS (Android is coming), with 1 GB of storage and one-minute videos on the free plan. Twice a week, a challenge suggests a memory to capture, like noting today's prices. Start small: three letters for three important dates, then add more over the years.

Frequently asked questions

What should I put in an open when letter?

Write to someone living exactly that situation: say you know how it feels, recall a memory that comforts or makes them smile, and end with one simple line about what you think of them. A photo or a voice message adds warmth.

Can I schedule an open when you're sad letter in Future?

Not as such: Future's series open on time (a set number of days after the previous one, a date, or an age), not on an emotion. You can choose dates that match moments when your loved one will want to hear from you.

How do I write a letter for every birthday?

Write ten lines each year: their age, one specific memory, what makes them laugh, a detail of the era, and a wish. You can also write several letters ahead of time and schedule each for its age.

Create your first capsule

Future is free on iOS, and coming soon to Android.

Get the app

Open When Letters: How to Write a Series That Opens Over Time