Connect banks with Teller

Teller connects Breadbox to US bank accounts using mutual TLS (mTLS) certificates instead of API keys. The experience from the admin dashboard is nearly identical to connecting with Plaid, but the onboarding curve is gentler: you can link real accounts on the free Development tier immediately, without applying for production access. Use Teller when your bank is supported and you want the fastest path to real-data testing, or when you prefer Teller’s coverage for your institutions.

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What you need

Before configuring Teller in Breadbox, you need:

• A Teller account — create one at teller.io.
• Your App ID (TELLER_APP_ID) from the Teller Dashboard.
• A certificate and private key (cert.pem and private-key.pem) issued by Teller from the Teller Dashboard. These files authenticate your application to the Teller API and are shared across all your Teller connections — they do not contain any per-user bank credentials.

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Teller environments

Teller has three environments, similar to Plaid: Unlike Plaid, the Teller environment is selected during the Teller Connect enrollment flow itself, not in the API configuration. All three environments use the same API base URL.

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Configure Teller in Breadbox

Teller credentials are supplied as environment variables. Set the following before starting Breadbox:

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Connect a bank account

Once Teller is configured, the connection flow from the admin dashboard works the same way as Plaid.

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How Teller authentication works

Teller uses mutual TLS (mTLS) to authenticate your Breadbox application. Every API request includes your certificate, which proves to Teller that the request comes from your registered application. Per-connection access tokens are then passed as HTTP Basic Auth credentials — Teller issues a unique access token for each bank enrollment, which Breadbox stores encrypted in your database. This two-layer model means:

1. The certificate identifies your application to Teller.
2. The access token identifies the specific bank enrollment (one per bank you link).

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Sync behavior

Teller syncs work on a date-range polling basis rather than the cursor-based approach Plaid uses. On each sync, Breadbox fetches transactions from a date window that overlaps with the previous sync by 10 days. This overlap ensures that any pending transactions that posted on a different date than they were authorized are captured correctly. The scheduled and webhook-driven sync mechanisms are identical to Plaid. When you configure a webhook URL in Breadbox Settings, Teller sends a notification when new transactions are processed, and Breadbox syncs immediately.

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Re-authentication

If your bank credentials change or your session at the bank expires, Teller sends an enrollment.disconnected webhook to Breadbox. The connection status changes to Re-auth Needed. To re-authenticate:

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Disconnecting a bank

To remove a Teller connection, click Remove Connection on the connection detail page and confirm the dialog. Removing a connection:

• Calls Teller’s API to revoke the enrollment and invalidate the access token.
• Sets the connection status to Disconnected in Breadbox.
• Preserves all transaction history. Previously synced transactions remain in your database.

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Connection management

All connection management actions — viewing account balances, sync history, triggering a manual sync, re-authenticating, and removing — are identical for Teller and Plaid connections. See the connections overview for a full description of connection statuses and dashboard controls, or the Connections API for the same operations exposed programmatically.