Buffer for Cards

Introducing Buffer: An innovative solution for card payments

Buffer is an add-on card product that aims to transform the way payments are made. Enable your customers to link non-fiat accounts that have different types of investments – such as crypto or exchange-traded funds – to a payment card.

Buffer takes the hassle away from your customers to first sell, exchange or liquidate investments and assets, then transfer them to the desired account so they're finally available – often days later.

With our payment cards equipped with Buffer, your customers will notice no difference at the point of sale, but will pay seamlessly.

Access investments immediately

Buffer opens up a range of new service opportunities based on the cardholder's investments and offers the customer a real choice to access funds when needed.

When things get tight on the checking account, Buffer allows your customers to switch to an alternative source of funding in the background: flexibility has never been so easy.

Your customers benefit from an unparalleled user experience.

Used by partners such as:

See our payment card options

Within seconds, the transaction is complete

Branded payment cards

Offer your own payment cards, made from eco-friendly and premium materials. We support both digital and physical cards – of course, with digital wallet capabilities.

Buffer for more liquidity

Enable your customers to take advantage of Buffer, which can be bundled with all payment cards – simply connect, simply pay.

Real-time authorization

With our unique technology package, it takes only seconds to check available funds and boost your customers' liquidity.

Easy Spend Control

Give your customers more than just a piece of plastic, wood or metal. Provide them with a payment card that gives them full control over their finances and allows them to spend from secondary non-fiat funds.

Solving an investment dilemma

People who invest often face the problem of having to transfer money from one account to another so that the preferred payment card can always be used.

It takes time, multiple apps need to be installed, and if the customer is offline, it may not work at all. Especially when it comes to very different types of investments, such as stocks, exchange-traded funds, or cryptocurrencies.

Buffer helps your customers solve this time-consuming task - elegantly and efficiently.

Boost your co-branded payment cards with Buffer

Fully safeguarded

We offer you a special and highly secure ring-fenced account, through which all your customers' accesses are handled. We manage only the transactions. The capital in this account is always your property.

Easy to integrate

Solaris partners don't need a new application to integrate Buffer – we just add it as an additional service. Our APIs make this a smooth process.

Create more payment options

Your customers can simply use shares of investments or assets, even precious metals, to make payments without having to worry about conversions and transfers. A smart digital conversion service enables real-time monetization of all types of funds.

Thankful customers

With Buffer, you give your customers more choice, access and control over their finances, empowering them to manage their funds and investments the way they want.

Our API - elegant and easy to integrate


Provide your customers with real time information on all cash movements on their accounts.

Sample endpoints of our API
POST /persons/:person_id/accounts

Our accounts support various payment methods, including SEPA Credit Transfers and SEPA Direct Debits, as well as different authorization flows.

Sample endpoints of our API
POST /persons/:person_id/accounts/:account_id/transactions/sepa_credit_transfer

Provide real-time notifications and alerts to your customers, such as new account bookings or successful card transactions. Our webhooks support flexible workflows and event-driven process flows.

Sample endpoints of our API
POST /webhooks

Make your financial services more powerful with Buffer