For developers
The age verification API for developers
One REST call starts a check, the user proves they're over 18 from their EU Digital Identity Wallet, and a signed result lands on your webhook. No SDK, no documents to handle, and no personal data to store.
Tessio is a plain REST API. You POST an age check, you get back a hosted verification link and a check id, and the signed result comes to you over a webhook. There is nothing to install, no document capture to build and no identity data to warehouse. You can integrate against the sandbox today.
If you would rather run the verifier yourself, the core is open source. Tessio.Verifier is an ASP.NET Core library on NuGet for .NET 8 to 10, under Apache-2.0, and it does OpenID4VP, SD-JWT VC and mdoc. Cloud is the hosted version of the same core.
One API, no SDK
POST to /v1/age-checks and present the returned link as a QR code or a deep link. No SDK to install and no documents to handle. Omit the body to verify age_over_18.
Webhooks and idempotency
Register a webhook and verify the HMAC signature before you trust an event. Send an Idempotency-Key so retries return the original check. Polling stays available as a fallback.
No personal data
A check returns an over-18 boolean, not a date of birth or a document. There is no selfie and no ID scan, so there is nothing for you to store or secure.
Open source and self hostable
The core is Tessio.Verifier, ASP.NET Core, Apache-2.0, on NuGet for .NET 8 to 10. Run it hosted as Tessio Cloud, or self host it on your own stack.
Start a check
One POST creates a check and returns a link for the user's wallet. The signed result comes back on your webhook. Everything is in the developer docs.
curl -X POST https://api.tessio.eu/v1/age-checks \
-H "Authorization: Bearer tk_live_your_key" \
-H "Content-Type: application/json" \
-H "Idempotency-Key: order-4821" \
-d '{ "minAge": 18, "reference": "order-4821" }'Frequently asked
Is there an SDK to install?
No SDK needed. It's a plain REST API you can call with curl or your HTTP client of choice. If you want the verifier as a library, the open source Tessio.Verifier is on NuGet for .NET.
What do I get back?
A signed over-18 yes or no. Register a webhook to receive results, or poll GET /v1/age-checks/{id} as a fallback. The result carries the boolean you need and no personal data.
Can I self host it?
Yes. Tessio Cloud runs on the open source Tessio.Verifier, an ASP.NET Core library on NuGet under Apache-2.0 for .NET 8 to 10. You can run the verifier inside your own environment.
Keep exploring
For developers
Build against the sandbox
Request access to get a project API key and integrate against the sandbox today. It's invite only while we onboard design partners, and design partners get preferential pricing.