> ## Documentation Index
> Fetch the complete documentation index at: https://agenticbanking.backbase.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Banking OS APIs

> Banking OS unified APIs define a vendor-neutral contract between the Backbase Engagement Banking Platform and connectors.

Each connector implements exactly one Banking OS unified API specification. You use the same interface for each capability, no matter which core banking system or third-party vendor the connector uses.

<CardGroup cols={2}>
  <Card title="API playground" icon="code" href="/banking-os-apis/api-playground">
    Browse the unified API specifications by calendar version (CalVer).
  </Card>

  <Card title="Error codes" icon="triangle-exclamation" href="/banking-os-apis/error-codes">
    Look up the error codes that the unified APIs return.
  </Card>
</CardGroup>