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Proof of Call · Free

Call it before it happens. Prove it forever.

Stamp any prediction to the Bitcoin blockchain: a free, public timestamp that proves you called it before it happened. Impossible to fake or backdate. The only “I called it” that actually holds up.

No account · no wallet · anchored via OpenTimestamps

Your words are hashed and anchored to the Bitcoin blockchain: free, public, and impossible to fake or backdate.

How to stamp a prediction to the Bitcoin blockchain

01

Write your call

Any prediction: a coin, a score, a headline, a hot take. Be specific enough that everyone will know if you were right.

02

We seal it to Bitcoin

Your exact words are hashed (SHA-256) and anchored to the Bitcoin blockchain via OpenTimestamps. Permanent, public, impossible to edit or backdate.

03

Prove it, forever

Share the receipt now to call your shot; reveal it when you're right. Anyone can verify the timestamp themselves, with no account and no trusting us.

Why it matters

Crypto is wall-to-wall with “I called it” screenshots, and almost all of them are fake, cropped, or backdated. That's why nobody believes them anymore.

A Proof of Call is the opposite. It's like calling your shot in front of a witness who can't be bribed or edited: the Bitcoin blockchain. Make the call, seal it, and when you're right, the receipt does the arguing for you.

Learn more

Guide

How to prove you called a crypto trade

Why 'I called it' screenshots are worthless, and the one way to prove a call that can't be faked or backdated.

Read more →Guide

How to timestamp text to Bitcoin, free

Anchor any text to the Bitcoin blockchain in seconds with OpenTimestamps, and verify it yourself later.

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Frequently asked questions

How do I prove I predicted something first?
Stamp your prediction here before the outcome is known. Your exact words are hashed and anchored to the Bitcoin blockchain, creating a public timestamp that can't be forged or backdated. When you turn out to be right, the receipt proves you said it first, with no screenshots and no trust required.
Is this a free blockchain timestamp?
Yes. It's a free, OpenTimestamps-based timestamp anchored to Bitcoin, with no account and no crypto wallet. The calendar servers batch thousands of stamps into a single Bitcoin transaction, so anchoring a call costs effectively nothing.
How is this different from screenshotting my prediction?
A screenshot can be faked or backdated in seconds, which is why nobody believes them. A Proof of Call is hashed and anchored to the Bitcoin blockchain at the moment you make it, so the timestamp can't be forged, and anyone can independently verify you said it before the outcome.
Can I timestamp any text, or just crypto calls?
Any text. Crypto calls, sports and election predictions, market views, or an idea you want to timestamp before you share it. The tool stamps whatever you write.
How do I verify an OpenTimestamps proof?
Open the verify link, or paste it on the Verify tab, and Sentari re-derives the hash and checks the Bitcoin attestation for you. You can also verify the raw .ots file yourself with the standard open-source ots tool, no website required.
Do I have to trust Sentari?
No. The proof is anchored to Bitcoin, not to us. Anyone can verify it with the standard open-source ots tool or at sentaritrader.com/verify, without permission from any company or server. That's the whole point.
When is it confirmed on Bitcoin?
The commitment is recorded instantly with the OpenTimestamps calendar; the Bitcoin attestation typically lands within a few hours, after which the proof is permanent and independently verifiable forever.

Sentari provides software and information, not financial advice. Crypto trading involves risk, including the loss of capital. Past performance is not a guarantee of future results.