Unzer

At a glance

Availability: Experimental (how to enable).
Auth: Basic auth.
Connection: HTTP Basic auth with UNZER_PRIVATE_KEY as the username and UNZER_API_PASSWORD as the password.
Docs: https://docs.unzer.com/server-side-integration/api-basics/authentication/

Set these per environment. See Connect an integration.

Variable	Required	Description
`UNZER_PRIVATE_KEY`	Yes	Unzer private API key (s-priv-… for sandbox, p-priv-… for production), used as the HTTP Basic username Docs.
`UNZER_API_PASSWORD`	No	HTTP Basic password for the Unzer API - always empty, leave as the default empty string Docs.

Get Unzer API keys: Request a free test account at https://docs.unzer.com/ (or sign an Unzer contract for production). You receive a key pair per environment: a public key (s-pub-… / p-pub-…) and a private key (s-priv-… / p-priv-…).
Set environment variables: Add UNZER_PRIVATE_KEY=s-priv-… (sandbox) or p-priv-… (production) to your .env. Leave UNZER_API_PASSWORD empty - the API authenticates with HTTP Basic using the private key as the username and an empty password.
Create a payment type: Charges require a payment type ID (e.g. s-crd-… for a card) created client-side via Unzer UI components or the payment types API, so that raw card data never touches your server.
Verify access: Run Get Payment with a known payment ID, or create a small test charge in sandbox with a test payment type ID.

Never use the public key (s-pub-/p-pub-) for server-side calls; only the private key authenticates this API. Keep it secret.
Sandbox keys (s-priv-…) and production keys (p-priv-…) both target https://api.unzer.com - the key prefix determines the environment.
Amounts are in the currency’s major units (e.g. 49.99 EUR).

Tool	Access	Description
Get Payment	Read	Retrieve a payment resource with its state, amounts (total, charged, canceled, remaining), and linked transactions
Get Charge	Read	Retrieve a specific charge transaction of a payment, including amount, status, and processing details
Create Charge	Write	Directly charge a payment type (one-step payment without prior authorization) using a payment type ID
Refund Charge	Write	Cancel (refund) a charge fully or partially, returning money to the customer
Authorize Payment	Write	Reserve funds on a payment type without charging yet (first step of the two-step authorize-then-charge flow, e.g. charge on shipment); reservations are held for about 7 days
Charge Authorization	Write	Capture a previously authorized payment, fully (empty body) or partially (with amount) - the second step of the authorize-then-charge flow
Cancel Authorization	Write	Cancel (reverse) an uncaptured authorization fully or partially, releasing the reserved funds - distinct from refunding a charge

Look up an Unzer payment I specify and summarize its state and the total, charged, canceled, and remaining amounts.
Refund a charge on an Unzer payment I specify and confirm the refunded amount.