Solaris, the Berlin-based embedded finance bank, has gone live on ACI Connetic for its SEPA Instant payments. ACI Worldwide announced the move on September 24, 2026. The go-live completes the first phase of a wider payments modernization. The Solaris SEPA Instant stack now runs on ACI’s cloud-native platform, which combines payment processing, orchestration, fraud prevention and payments intelligence. Financial terms were not disclosed.

Most infrastructure migrations are dull, and this one would be too at almost any other bank. Solaris sells payments to other brands, and EU rules have made instant euro payments a legal obligation. That makes the choice of platform matter more than usual.

What the Solaris SEPA Instant Migration Involves

Solaris picked ACI Connetic on September 29, 2025, with SEPA Instant as the first workload to move. Almost exactly a year later, the ACI release says the Solaris SEPA Instant go-live happened on schedule. Solaris plans to move more of its payments infrastructure onto Connetic over time, as part of a long-term transformation.

ACI’s pitch for Connetic is simple. A bank runs processing, fraud screening and routing in one architecture instead of stitching separate systems together. ACI keeps extending it. On September 22, it added support for payments orchestrated through Swift’s blockchain ledger, including tokenized deposits. Solaris is a useful reference customer because its volume comes from many partner brands at once.

Steffen Jentsch, CEO of Solaris, said the platform lets Solaris deploy “AI-driven, highly resilient payment processes” as it matures into what he calls a Financial-Platform-as-a-Service provider. ACI CEO Thomas Warsop framed it as a platform decision that banks across Europe are making as they rebuild payments around instant.

Why the Regulation Forces the Solaris SEPA Instant Upgrade

The EU Instant Payments Regulation requires euro-area payment providers to receive instant credit transfers. They must also send them at no higher price than a standard transfer. They must also check the payee’s name against the account before the payer authorizes a payment. For eurozone providers, the receiving deadline fell in January 2025, and the sending and Verification of Payee deadlines in October 2025.

SEPA Instant is therefore no longer a premium service with modest volume. It is everyday traffic that runs around the clock and must reach the payee within seconds. Fraud checks have to happen inside that same window. Systems built for overnight batches struggle with that load.

For most banks, instant payments are a compliance duty. For Solaris, they are part of the product. Solaris holds a full German banking license and provides accounts, cards, lending and payments to fintechs, consumer brands and multinationals. When a partner promises its users instant transfers, Solaris SEPA Instant is the rail underneath. An outage at an ordinary bank hits that bank’s customers. An outage at a banking-as-a-service provider hits every brand on its platform at once.

Solaris Needs Reliability More Than Most

Solaris has had a difficult few years. It spent a long period under BaFin scrutiny over its anti-money-laundering controls and went through a restructuring. In February 2025 it raised €140 million, with Japan’s SBI Group becoming majority shareholder.

The rebuild has continued under new leadership. Jentsch, previously a senior technology executive at flatexDEGIRO, replaced Carsten Höltkemeyer at the start of 2026. In March, Solaris announced a plan to become an AI-native bank, with AI agents running operational processes under human control. The same plan cut about 80 jobs, around a fifth of staff. It also set out an aim to become pan-European financial infrastructure.

Against that background, the detail that the go-live landed on schedule matters most. A banking-as-a-service provider trying to regain the confidence of partners and supervisors has to show it can run large technology projects without drama. Putting Solaris SEPA Instant on an established platform rather than building in-house is the conservative choice, and a sensible one. Solaris competes on its license and partner relationships, and custom payments plumbing adds little to either.

What It Means for Embedded Finance

There is a trade-off. Moving Solaris SEPA Instant and later services onto ACI deepens its dependence on one vendor for a core function. Migrations like this usually take several phases and several years. Solaris is also betting that the Connetic fraud layer holds up for instant payments at scale. There, a missed fraud signal cannot be fixed by recalling a batch.

A smaller headcount raises the stakes. With a fifth fewer staff and AI agents taking on operations, Solaris leans harder on vendors and automation.

For brands building on Solaris, the practical test is simple. Is the Solaris SEPA Instant service faster, cheaper to run and more reliable after the move than before it? Partners will judge that on uptime and on how many legitimate payments get stuck in fraud checks. The architecture will matter to them only if those numbers improve.

What to Watch

As of September 27, neither Solaris nor ACI had announced the phase after Solaris SEPA Instant or named the payment types that move next. Solaris had also announced no partner wins or losses since the go-live. Existing partners such as ADAC and Boerse Stuttgart Group were both named in the March plan. Their users would feel any change first.

The next milestone is that second phase, and whether Solaris publishes uptime or processing figures for Solaris SEPA Instant after the migration. A clean second phase would support the claim that Solaris has stabilized. It would also back its ambition to act as pan-European infrastructure for SBI.

For related coverage, see why CSI bought Qolo to extend its payments stack and what the Capgemini payments report says about tokenized money.

FintechBits covers payments, banking and fintech developments for readers in the US and UK. This article is for information only and is not financial advice. Views expressed are those of the FintechBits editorial team.