Sparkasse Iserlohn Open Banking & API Access | Guide

Sparkasse Iserlohn serves personal and business customers across the Märkischer Kreis in North Rhine-Westphalia, and its accounts can be reached through open-banking.io without any of the usual PSD2 friction. There are no eIDAS certificates to buy, no sandbox registration, and no bank-side developer onboarding. You link your account once in a browser, and open-banking.io keeps your balances and transactions in sync — while your data stays encrypted with a key that never leaves your device.

Because everything is decrypted locally, open-banking.io operates on a zero-knowledge basis: its servers only ever hold your public key, so nobody but you can read your Sparkasse Iserlohn statements.

How to connect Sparkasse Iserlohn

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

  1. Sign up for an open-banking.io account.
  2. Set an encryption passphrase. Your cryptographic keys are generated right there on your own device.
  3. In the dashboard, search for Sparkasse Iserlohn (BIC WELADED1ISL) and choose the account type you want to link — business or personal.
  4. You are redirected to Sparkasse Iserlohn's own secure login, where you approve access on the bank's PSD2 consent screen.
  5. Your accounts then sync back into your dashboard automatically.

Consent to Sparkasse Iserlohn lasts up to 180 days, after which you simply re-approve on the bank's screen to keep the connection live.

Access your data

Once an account is connected, reading it programmatically is an optional developer step. Open 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 you can use the CLI (openbanking accounts, openbanking transactions, openbanking sync), an SDK, or the REST API. Every request authenticates with the X-Api-Key header, and every response is decrypted locally with your own key. An API key on its own only ever returns ciphertext; without your private key the data stays unreadable — even to open-banking.io.

FAQ

Do I need a developer account with Sparkasse Iserlohn?

No. You never register with the bank as a developer. You approve access on Sparkasse Iserlohn's normal login screen, and open-banking.io handles the PSD2 plumbing.

What does it cost?

Around EUR 3 per month, covering access to 2,600+ EU and UK banks including Sparkasse Iserlohn.

Can the CLI connect my account?

No. The CLI, SDK, and API only read and sync connections you already made in the dashboard — there is no connect command.

Start linking your Sparkasse Iserlohn accounts at open-banking.io.