Sparkasse Hamm API Access & Open Banking Data

Reaching your Sparkasse Hamm accounts programmatically usually means wrestling with eIDAS certificates and a PSD2 sandbox. open-banking.io removes that entirely. It is a zero-knowledge, certificate-free bridge to 2,600+ EU and UK banks, and Sparkasse Hamm (BIC WELADED1HAM) is one of them. Both business and personal accounts are supported, and a single approval keeps your data flowing for up to 180 days before you renew.

The defining trait is where the keys live. When you sign up, your encryption keys are generated locally on your own device from a passphrase you choose. open-banking.io only ever holds your public key, so its servers store your Sparkasse Hamm balances and transactions as ciphertext they cannot read. Decryption happens on your machine, every time.

How to connect Sparkasse Hamm

Connecting happens 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 private key never leaves your device.
  2. In the dashboard, pick Sparkasse Hamm and choose the account type you need — business or personal.
  3. You are redirected to Sparkasse Hamm's own secure login, where you approve access on the bank's PSD2 consent screen. Your credentials go only to the bank.
  4. Your approved accounts sync back into the dashboard, ready to view. That consent stays valid for up to 180 days.

Access your data

Once Sparkasse Hamm is connected, reading the data in code is an optional developer step. On the Developers page, create an API key and export a credentials.json — it bundles the API key with your private decryption key. Then 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 API key alone returns only ciphertext — without your private key, the data stays unreadable, which is what zero-knowledge means in practice.

All of this runs at roughly EUR 3/month, with no certificate paperwork.

Does open-banking.io see my Sparkasse Hamm data?

No. It stores only your public key and encrypted data. Decryption occurs on your device with a key only you hold.

Do I need an API key to connect Sparkasse Hamm?

No. Connecting is done entirely in the dashboard via the bank's consent screen. API keys are only for optionally reading data afterwards.

How long does access last?

Sparkasse Hamm allows a maximum consent window of 180 days, after which you re-approve access in the dashboard.

Ready to start? Visit open-banking.io.