Sparkasse Siegen API Access & Open Banking Data

Sparkasse Siegen serves the Siegen-Wittgenstein region, and open-banking.io lets you reach its account data without certificates, eIDAS setups, or a bespoke PSD2 integration. Whether you hold a business or personal account (BIC WELADED1SIE), you can pull balances and transactions into one dashboard and, if you want, read them programmatically afterwards. Everything is decrypted on your own device with a key that never leaves it.

How to connect Sparkasse Siegen

Connecting happens entirely in 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 your encryption passphrase. Your key pair is generated locally on your device; open-banking.io only ever sees your public key.
  2. In the dashboard, search for Sparkasse Siegen and choose the account type you hold — business or personal.
  3. You are redirected to Sparkasse Siegen's own secure login, where you approve access under PSD2. Your credentials are entered only on the bank's site.
  4. Once you grant consent, your accounts sync into the open-banking.io dashboard. Consent lasts up to 180 days, after which you simply re-approve on the bank's screen.

Access your data

After your Sparkasse Siegen accounts are connected, developers can optionally read them programmatically. 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 every response is decrypted locally with your own key. The CLI and SDK only read and sync connections you already made in the dashboard — they cannot connect a bank. An API key on its own returns ciphertext; without your private key, the data stays unreadable.

Because the architecture is zero-knowledge, open-banking.io's servers can never decrypt your Sparkasse Siegen data. No QWAC or eIDAS certificate is required, and the service runs at roughly EUR 3/month.

Does open-banking.io store my banking password?

No. You enter your Sparkasse Siegen credentials only on the bank's own login page during PSD2 consent. open-banking.io never sees them.

Can I access both business and personal accounts?

Yes. Sparkasse Siegen supports both account types, and you pick the one you hold when connecting in the dashboard.

How long does access last?

Up to 180 days per consent. When it expires, re-approve on Sparkasse Siegen's consent screen to keep syncing.

Start at open-banking.io.