Send a message
into space.
SpaceSIO turns your words, photos, and video into real radio signals broadcast into space, each with a verifiable Certificate of Issuance.
Create the message · Issue the signal · Prove it was sent
> Emily, I love you forever, and our souls are together in the universe. But better.
This is a preview. See a real confirmed broadcast →
Three steps to the stars
No radio license, no antenna, no physics degree. We handle the hard part, so you just decide what to say to the universe.
Compose
Write a message, or attach a photo on a paid plan. Give it a title the cosmos will remember.
Transmit
Your data is converted into a real radio signal and transmitted into space. The transmitting station signs a confirmation it went out, and that's your proof.
Share
Every transmission gets its own page and a shareable link, plus an official certificate. Send it to friends and gather comments and reactions.
Radio waves don't stop at the sky
For decades, SETI, the Search for Extraterrestrial Intelligence, has pointed enormous antennas at the sky, listening for faint radio signals from distant civilizations. The premise is simple: radio waves travel across space, and a technological society might broadcast them.
SpaceSIO runs that in reverse. When you transmit, your message becomes a real radio wave radiating outward from Earth at the speed of light, the same kind of signal SETI hopes to one day catch coming from somewhere else.
Will anyone, anywhere, ever detect yours? We honestly don't know. It might fade into noise, or it might, ages from now, reach someone in a distant galaxy who's listening the way we listen. That uncertainty is the whole point.
Send a secret to the future
Schedule a signal and seal it, its words and images stay locked away from everyone, even in share previews. The page shows only a glowing capsule and a live countdown. The instant your signal goes on air, it unlocks for the world to read.
- Contents are hidden server-side until release, no peeking at the source, no leaking into link previews.
- A countdown ticks down to the exact moment it broadcasts and reveals.
- Everyone can still see a signal is waiting, just never what it says until it's on air.
Sealed until it goes on air
This is a time capsule. Its contents are locked and hidden from everyone, they unlock the instant the signal broadcasts into space.
Unlocks in
3d04h11m59sPhotos, actually transmitted
Attach a photo on a paid plan and a real thumbnail of it is broadcast over the air. The full image is archived on your page.
Comments & reactions
Every transmission is a place to gather. Friends react and comment in real time.
MCP for AI bots
Paid members get an MCP endpoint so AI agents can transmit on their behalf, programmatically.
Made to share
Beautiful share links with rich previews, so every signal looks great wherever you post it.
A real radio signal
This isn't a metaphor. Your data is genuinely converted into a radio signal and transmitted into space.
Priority queue
Higher tiers jump the transmit queue, so your message reaches the antenna sooner.
Immortalize someone in radio waves
Send a message, a memory, or a photo of someone you love into space, and get a beautiful, official Certificate of Issuance to give as a gift.
A birthday. An anniversary. A new baby. A goodbye. Their moment, broadcast to the cosmos and stamped with the exact date, time, frequency, and cryptographic proof it truly went out, something no one can take back and nothing on Earth can erase.
The perfect novelty gift for a friend, a partner, a parent, or a coworker who has everything. Cancel anytime.
Choose your transmit capacity
Start free with text beacons. Upgrade when you're ready to send pictures across the galaxy.
Ground Control
Say hello to the universe.
3 signals / month
- 3 text signals / month
- Up to 140 characters each
- 3 broadcasts each (initial + 2 daily echos)
- Public shareable links + certificate
- Your callsign profile page
Signal
Send pictures to the stars.
billed once a year
50 signals / month
- 50 signals / month
- Up to 500 characters each
- 6 broadcasts each (initial + 5 daily echos)
- Attach photos
- Add a link to your signal
- 50 MB media / month
- MCP access for AI bots
Broadcast
More signals, bigger stories.
billed once a year
100 signals / month
- 100 signals / month
- Up to 1,000 characters each
- 8 broadcasts each (initial + 7 daily echos)
- Photos & video
- Add a link to your signal
- 200 MB media / month
- Priority transmit queue
- Verified callsign badge
Interstellar
Broadcast like a civilization.
billed once a year
500 signals / month
- 500 signals / month
- Up to 2,000 characters each
- 11 broadcasts each (initial + 10 daily echos)
- Photos & video
- Add a link to your signal
- 500 MB media / month
- Top transmit-queue priority
- High-throughput MCP for AI fleets
Questions from Earth
Is my message really transmitted?+
Yes. Your data is converted into a real radio signal and transmitted into space over the air. The transmitting station signs a confirmation the moment it airs your packet, and you get a proof page for every transmission.
Does it actually reach anyone out there?+
Honestly, we can't promise anyone, or anything, receives it. What we can promise is that your message becomes a genuine radio signal that leaves our antenna, with verifiable proof it was transmitted. Radio waves travel outward at the speed of light.
What can I send?+
Free accounts send short text signals (up to 140 characters). Paid plans unlock longer messages and let you attach a photo, which is transmitted as a thumbnail and archived in full on your shareable page.
Do you transmit my whole photo?+
We transmit a small thumbnail of your actual photo over the air, a recognizable version of the image genuinely travels as radio data, so it doesn't depend on our website surviving. The full-resolution file is archived on your page, and a SHA-256 hash lets anyone verify it.
What proof do I get?+
Each transmission gets a certificate: a timestamp, the frequency, the exact packet sent, a payload hash, and a signed confirmation from the transmitting station that the signal went out.
Can AI bots transmit for me?+
Yes. Paid plans include an MCP endpoint so AI agents can transmit on your behalf, programmatically.
The universe is listening.
Your first transmission is free and takes thirty seconds. What will you say?
Send your first signal