Letterbox

Letterbox vs Slowly

Letterbox vs Slowly.
Two different ideas of a letter.

Slowly is a pen-pal app that matches you with strangers. Letterbox is a private letterbox for people you already know and love.

If you want to write to someone you already care about \u2014 use Letterbox. If you want to meet strangers by trading slow letters \u2014 use Slowly.

Try Letterbox free

Slowly and Letterbox both use the word “letter,” but they’re different products solving different problems. Slowly is a mobile pen-pal app: you get matched with a stranger, letters take real travel time to “arrive,” and the experience leans social — profiles, stamps, languages, a community of strangers.

Letterbox is a private letter vault. You write letters to specific people you already know: your mom, your kid, your ex, your future self. Each letter lives at a private URL, locked behind a secret question only the recipient would know. There’s no matching, no feed, no strangers.

Both are good at what they do. They’re just not the same thing.

Feature by feature

Letterbox vs Slowly.

FeatureLetterboxSlowly
RecipientAnyone you knowStranger you're matched with
Private by default

Matched pen pals read your letters

Secret-question lock
Scheduled delivery

Slowly uses travel-time delay

“Open When…” sealed envelopes
After I'm Gone posthumous delivery
Dead Man's Switch
Anonymous writing

Slowly requires a profile

Voice letters
Recipient needs an account
Shared letterbox URL
Mobile app (iOS/Android)Web first
Pen-pal matching
Stamp collecting / gamification
Public letters wallOpt-in
PricingFree forever. Pro $99 one-time. Max $199 one-time.Free tier with ads. Slowly Plus subscription ~$5.99/mo.

What each one is actually good at.

Letterbox is better for:

  • Writing to specific people you already know
  • Private letters with secret-question locks
  • Scheduled delivery (open on a date)
  • “Open When…” sealed envelopes
  • After I'm Gone / posthumous delivery
  • No account needed for recipients
  • One-time payment, no subscription
  • Public opt-in wall (if you want strangers)

Slowly is better for:

  • Meeting strangers who also like slow correspondence
  • Mobile-first, iPhone/Android native
  • Matching by interests, language, location
  • Virtual stamps and country collecting
  • Gamified pen-pal experience
  • Social / community features

Use Slowly if:

You want to make new friends across the world through letters. You like the novelty of a letter that takes 24 hours to “arrive.” You want something mobile-first that feels like a game. You specifically want to write to strangers, not people you already know.

Use Letterbox if:

You already know who you want to write to. You want a private page where every letter to that person lives (a real “letterbox” for them). You want optional scheduled delivery, secret-question locks, and posthumous options. You want to pay once and own your letters forever instead of a subscription.

Letterbox vs Slowly — FAQ.

Can I use Slowly to write to my mom?+
Technically yes, if she downloads the app and signs up. But Slowly is built around the pen-pal matching model — it's not where most people put letters to family. Letterbox is designed for that case: no account needed for your mom, just a link and a secret question only she'd know.
Can I use Letterbox to meet strangers like Slowly?+
Partially. You can turn on a public letterbox (an opt-in inbox for strangers), and we're building a public letters wall for anonymous sharing. But Letterbox is not a matching service. If your main goal is to meet new pen pals globally, Slowly is better for that.
Is Slowly worth the subscription?+
If you love the pen-pal experience and write to strangers regularly, Slowly Plus is reasonable. If you're writing primarily to specific people you already know, you're paying for features you don't use. Letterbox's one-time pricing is cheaper long-term for that use case.
Which has better privacy?+
Letterbox. Each letter is locked behind a secret question only the intended recipient would know, letter pages are not indexed by search engines, and we don't share your data with advertisers. Slowly's matched pen pals can read your letters, and the app uses your data for matching and recommendations.
Can I switch between them?+
Sure. They're solving different problems — a lot of people use both. Use Slowly for international pen pals, use Letterbox for letters to the people in your actual life.

Keep writing

Keep exploring

Letterbox vs FutureMe

For letters to your future self.

Letterbox vs Email

Why a letter isn't a better email.

Unsent letters

The letters you're writing in your head.

Love letters

When the recipient is someone you love.

Letters to your kids

Private time capsules for your children.

Long-distance letters

For partners, friends, family far away.

Try Letterbox free.

One recipient, unlimited letters, forever free. Upgrade only if you need more.

Claim your letterbox

Free forever. No credit card.