Two kits. Two mailboxes.One tradition.
A monthly letter-writing kit for both your grandparent and grandchild. Pre-stamped. Pre-addressed. With fun sparks. Just write and mail.
Stay connected from afar
Both people get a kit every month
Large print for grandparents, colorful designs for kids. Within a week, both have a handwritten letter from someone they love.Spark card
Fun for kids, warm for grandparents. Fresh every month, never repeats.
Pre-stamped envelope
USPS Forever stamp. Already addressed. Seal it and mail it.
Nothing to figure out
No stamps to buy. No addresses to look up. No staring at a blank page.
Three steps. That's it.
Pick your pair
Grandparent & grandchild, long-distance couple, college kid & parent. Enter their addresses and we handle the rest.
Kits arrive each month
Each person gets a spark card and a pre-stamped, pre-addressed envelope to the other person.
Write, seal, mail
Fill out the card, slip it in the envelope, drop it in a mailbox. That's the whole thing.
Not a gift box. A tradition.
Everyone intends to stay in touch
Heartstring makes it actually happen.Both sides write
It's not one-way. Both people send, both people receive.
Sparks do the hard part
No blank page anxiety. Guided, fun, age-appropriate.
Letters become keepsakes
The fridge fills up. The shoebox fills up. The distance shrinks.
Simple pricing. Everything included.
Kits, stamps, addressing, and fresh sparks every month. No hidden fees.
Monthly
Cancel anytime
- Kits for both people
- Pre-stamped USPS Forever envelopes
- Pre-addressed to each other
- Fresh sparks each month
- Age-appropriate designs
- Free shipping
3-Month Gift
Three months of letters
- Everything in Monthly
- 3 months for both people
6-Month Gift
Best value
- Everything in Monthly
- 6 months for both people
- Save over $20
Questions
What comes in each kit?
A spark card designed for their age, a pre-stamped USPS Forever envelope addressed to the other person, and simple instructions.
Who is this for?
Any two people who want to stay in touch. Most popular: grandparent + grandchild (ages 5–14). Also great for long-distance couples and college kids & parents.
How do gift subscriptions work?
Enter both addresses, pick a plan, add a gift message. Kits start arriving the next month.
What if my grandchild is too young to write?
For little ones who can't write yet, we have sparks for parents to fill in about their child's journey through life — milestones, funny moments, favorites — plus mementos like hand tracings. Grandparents love these.
Do sparks repeat?
Never. Fresh every month.
Why not just buy stamps myself?
You could. Most people intend to. But the small barriers add up and it never happens. Heartstring removes every barrier except the writing.
Can I change addresses?
Yes, anytime from your dashboard. Changes apply to the next kit. US addresses only for now.
The gift that arrives in both their mailboxes
$19.99/month for both people. Cancel anytime.