Curve, a UK-based fintech firm which allows consolidation of all debit and credit cards into one card, has added support for American Express (Amex) cards in its Beta.

Amex customers will be able to add their cards to Curve, and spend anywhere the Curve Mastercard is accepted.

Curve said that this solves the challenge that Amex cardholders face when certain retailers do not accept their cards due to higher fees.

The fintech has been trialling Amex compatibility with its platform in closed Beta since November last year.

During the test phase, at least 500 Curve users spent more than £1m on their Amex by paying with Curve.

While spending with Curve card, Amex cardholders can continue to earn American Express Membership Rewards points along with additional Curve Rewards points.

Curve offers rewards on purchases at 50 major brands such as Amazon, Uber, Tesco, Sainsbury’s, Waitrose, Ocado, Selfridges and BP.

Launched in January last year, Curve intends to simplify money management by allowing customers to add all their cards to a single Curve Mastercard.

Users can switch payments between cards up to two weeks after a purchase. Curve cards can be used for contactless, chip & PIN, magstripe transactions as well as ATM withdrawals.

In September, the firm went on to eliminate hidden card fees, targeting customers who use their card to spend money abroad. This avoids the usual currency exchange fees charged.