Security & trust — how verifiable an Akkubrief is

Updated: 21.07.2026

Trust isn't claimed, it's made verifiable. This page sums up what secures an Akkubrief technically — traceable rather than on faith.

Signed and verifiable in the browser

Every certificate is cryptographically signed with Ed25519. Verification runs entirely in the buyer's browser (WebCrypto): verify the signature, recompute the certificate ID against the content, optionally match the vehicle identification number. Any later change is immediately visible — including reusing someone else's certificate. The VIN appears only masked and as a SHA-256 checksum, never in clear text. You don't have to trust us — you can check it yourself.

Read-only access — your car stays yours

Sign-in happens directly at Tesla, not with us. We only ever receive read permissions on driving and charging data: no password, no vehicle control, no unlocking, no waking the vehicle. You can revoke access anytime in your Tesla account.

Data-minimal and protected

Vehicle data is stored encrypted and never sold. We use no cookie trackers. Akkubrief runs on ISO 27001 and SOC 2 certified infrastructure (Supabase, Vercel). You can request deletion of your data at any time.

Calculated in the open

No provider on the market discloses how its battery score is produced — we do. How we compute battery health from the charging history, where the limits are, and what an Akkubrief is not, is documented in full in our methodology.

No result, no charge

If the data isn't enough for a reliable certificate, we don't issue one — and charge nothing. An Akkubrief is a data-based estimate of battery health, not an official document and not a guarantee.