Isbank Germany API Access & Open Banking Guide

Isbank GmbH is the German arm of Türkiye İş Bankası, serving both retail customers and businesses. With open-banking.io you can link your Isbank accounts (BIC ISBKDEFXXXX) and pull balances and transactions into one place — without certificates, without a bank-side developer contract, and without ever handing your data to a third party in readable form.

open-banking.io is a zero-knowledge service covering 2,600+ EU and UK banks for roughly EUR 3/month. Your encryption keys are generated on your own device, so the platform only ever holds your public key. Every response you retrieve is decrypted locally — the servers store ciphertext they cannot read.

How to connect Isbank

Connecting happens entirely inside the open-banking.io dashboard — there is no API call, code, or key involved in this step.

  1. Sign up for open-banking.io and set an encryption passphrase. Your private decryption key is created locally at this moment.
  2. In the dashboard, search for Isbank (Germany) and choose your account type — business or personal.
  3. You are redirected to Isbank's own secure login, where you approve access under PSD2.
  4. Your accounts sync back into the dashboard. Under PSD2 rules the consent lasts up to 180 days, after which you simply re-approve on Isbank's screen.

That's the whole flow — you authenticate directly with Isbank, and open-banking.io never sees your banking credentials.

Access your data

Programmatic access is an optional step for developers, available only after a connection exists. On the Developers page, create an API key and export a credentials.json — this bundles the API key together with your private decryption key.

From there, use the CLI (openbanking accounts, openbanking transactions, openbanking sync), an SDK, or the REST API. Requests authenticate with the X-Api-Key header, and each response is decrypted on your machine with your own key. The API key alone returns only ciphertext — without your private key it stays unreadable. Note these tools read and sync existing connections; they never create one.

FAQ

Do I need a developer agreement with Isbank?

No. Access is granted through the standard PSD2 consent screen at Isbank's own login — no certificates or bank contracts required.

Can open-banking.io read my Isbank transactions?

No. It is zero-knowledge and holds only your public key. Data is decrypted locally with a key only you control.

How long does my Isbank connection stay active?

Up to 180 days per consent, the PSD2 maximum. Re-approve on Isbank's screen to renew.

Ready to start? Visit open-banking.io.