Proof of who, where and when.

Identity verification that leaves evidence. Tsubacheck is the engine that turns a person, a place and a moment into proof that an auditor, a regulator or a judge can check.

Talk to the team → See the engine

evidence / evd_7Xk2Q9 Verified

Certified presence report: verified selfie, coordinates, time and blockchain seal.

Verification record

Identity Liveness check passed 09:41:02
Document Matches the face 09:41:04
Presence 42.5063, 1.5218 · 4 signals 09:41:05
Time External clock 09:41:07
Integrity Sealed on blockchain 09:41:09

Signed report · PAdES LTA · eIDAS 2

Real engine output in ResidenceSafe. Sample data.

Companies and institutions already using the engine

sealed check-ins: 48,000+
registered users: 2,800+
signatures with evidence: 750,000+
companies and institutions: 13

Internal data, February 2026.

01 The problem

Almost everything we use to prove something online was never designed as proof.

~~Password~~
~~SMS code~~
~~Screenshot~~
~~Electricity bill~~
~~Signature on a PDF~~
~~Google Maps history~~

They can be shared, edited or generated with AI in seconds. They show which device was used, or that someone paid. They do not show who was there, or where, or when.

02 The engine

Four layers. One record.

Tsubacheck identity verification checks all four layers at once. If one fails, there is no proof. If all four pass, you get digital evidence with a chain of custody that does not rely on our word.

01
Identity
Who?

Biometrics with liveness detection, matched against the official document. Detects masks, deepfakes and injected video.
liveness: passed
02
Presence
Where?

Location cross-checked against several independent signals, with device and SIM verification at operator level.
geo: 42.5063, 1.5218
03
Time
When?

Timestamp from an external clock, not the phone. Once recorded, nobody can move the date.
ts: 2026-10-26T09:41Z
04
Integrity
Can it be trusted?

Blockchain fingerprint and signed report. A third party checks it independently, without relying on us.
seal: 0x7af3…c904

03 Integrate

An engine that plugs into your flow.

What ResidenceSafe and TsubaSign do in their apps, your platform can request through an identity verification API or as white label: check a person before a payment, an access, a signature or a consent, and keep the evidence.

Early access to the API →

POST /v1/evidence 201

{
  "id": "evd_7Xk2Q9",
  "action": "contract.sign",
  "identity": { "liveness": "passed", "document": "matched" },
  "presence": { "lat": 42.5063, "lng": 1.5218, "signals": 4 },
  "time":     { "source": "external", "at": "2026-10-26T09:41:07Z" },
  "integrity":{ "anchor": "0x7af3…e8b1c904", "report": "pades-lta" }
}

Illustrative example. The API is in early access.

04 Built on Tsubacheck

Same engine. Two products.

Tax residency · B2C · Formerly Tsubacheck Honor

ResidenceSafe

Thirty seconds a day to prove where you have been.

A daily selfie check-in that leaves a certified record of physical presence. For expats, digital nomads and their tax advisers.

residencesafe.com ↗

Service agreement

Laura M. · Signer 1 of 2

Advanced electronic signature ✓ Verified

Identity: Biometrics + OTP
Date: 26/10/2026 09:41 UTC
Place: Andorra la Vella
Hash: sha256 9f2c…a71e

Electronic signature · B2B · Formerly Tsubacheck Companion

TsubaSign

A signature that proves who signed.

Electronic signature with identity verification, timestamping and custody of the evidence at every step. For law firms, HR, insurance and regulated sectors.

tsubasign.com ↗

05 Sectors