Only got five minutes? Here are the key takeaways 

• A sidecar approach runs a modern core alongside your legacy one and moves customers and products across piece by piece, domain by domain. 

• Your legacy core keeps running the bank while the sidecar runs everything new including products, channels, partners and AI. Consolidated summaries post back to your ledger so nothing gets lost between the two. 

• In this way, you can structure anything you’re migrating before you move it. AI tooling can now scan a legacy core and surface undocumented information and rules before day one of the project. 

• Oradian is a proven product engine that launches new products in 60 days, with 750+ native APIs to connect your ecosystem, 99.98% uptime and 8,800 transactions per second to fuel your growth. Book a call with vanda.jirasek@oradian.com to start working on Oradian.  

Sidecar core: migrate without the risk 

Many banks have lived through a failed core project where their chosen vendor seemed great, only for migration to go terribly because when you dig into a twenty-year-old system, you always find surprises: 

• Custom business rules hidden in undocumented code 

• Forgotten integrations that break the moment you switch off the old box 

• Old customer records put together using manual workarounds 

• Messy data that only shows up six months into the project, right when the launch date is already public 

Trying to move all of that at once with a hard deadline is too great a risk for any bank.   

Instead of ripping out the old system, use a sidecar. You implement a fast new core next to your old one and move things over one piece at a time. Call it a mini-core or a product engine. 

Here is how it works: 

• Your old core stays where it is: It keeps running your main accounting books, government reporting, old accounts, and existing customers. It acts as your baseline safety net. 

• The sidecar handles anything new: All new products, mobile features, business partners, and AI tools run here. It syncs data with the old system and sends quick total numbers back to the main ledger instantly. 

• Integrate your apps: Mobile apps and web portals send customers to whichever core holds their specific product. Over time, more traffic naturally shifts toward the sidecar. 

• Plug in partners: Fintech tools, ID checks, fraud prevention, and cloud services connect straight to the sidecar through simple modern connections, skipping the headache of linking to old code. 

All your high-speed tech, including AI credit checks, instant sign-ups, live payment processing, and cloud lending, live on the sidecar right from the start, so you get modern features today without waiting years to shut down the old box. 

How to migrate easily 

A sidecar lets you move at your own pace. Here’s how to do it: 

• Select a product or market: Launch your next product on the sidecar before moving a single line of old data. Whether it's a new credit line, a digital wallet, or a merchant lending deal, build it on the sidecar first. Nothing on the old core breaks, and your team gets comfortable with the new tech. 

• Move one specific area at a time: Pick a single product line, like SME loans, and move it over entirely: rules, history, and customer accounts. Structure it, run it in parallel, and get comfortable that there’s nothing to fix. 

• Repeat the process: Each section gets easier. Once lending is over, move to deposits, then cards. The old core shrinks piece by piece without a big shut-down date. 

You can now bring new products to market, innovate with AI, and give your teams the tools they need to succeed without risking your bank.  

Plan before you migrate 

All this means that teams can now inspect the legacy core before moving a single file. AI-native agents read through old code to pull out hidden business rules, forgotten integrations, and unstructured data records before work starts, rather than leaving your team to discover them halfway through the migration project. Mapping still takes effort, but work done at the start makes fixes easier. Map first, then ship.  

Benefits of the sidecar approach 

• Sustainable growth: If something stops working, it only stops in one domain on one system, and the bank keeps running. 

• Grow now: New products launch on the sidecar in weeks, while the legacy core carries on, so you don’t need to wait two years for revenue. 

• Your team in control:  

• No code for product and risk to set rates, fees and eligibility 

• Low code for engineers to connect channels, rails and partners through APIs 

• Your code for custom builds that are governed and auditable with Oradian’s AI agent helping author them 

• Reversibility: Every domain migration runs in parallel until you’re satisfied, making roll backs easy. 

• Ecosystem access: Partners, KYC, fraud and data providers connect once, to the sidecar, through a modern API surface.  

• AI on live data: Your AI models and agents work against the sidecar’s governed data, so limits, pricing and risk decisions respond to what customers are doing now. MIT’s Project NANDA found that roughly 95% of enterprise generative AI pilots deliver zero measurable return and the cause sits in the data and integration layer underneath them. A sidecar gives you that layer without a core replacement. 

Oradian: the product engine built for growth 

Oradian’s product engine is the sidecar you need to grow without risk in 2027 and beyond. It runs alongside your existing core, launches products in weeks, not months, from decision to live, and connects to your ecosystem through 750+ native API endpoints that stay backwards compatible, so the integrations you build for domain one still work when you move domain five. 

Oradian runs at 99.98% uptime and handles 8,800 transactions per second, with up to 12,000 journal entries per second on real-time wallet accounts, while your main core receives clean consolidated summaries and stays stable. Governed access to your operational data through Database Access gives your risk, finance and AI teams a complete, current view without loading the system serving customers. 

With Oradian, Salmon achieved a 200x increase in monthly lending throughput and 648% loan portfolio growth in twelve months. Esquire Financing tripled its loan portfolio. FairMoney processes over 8,000 loan applications a day on a single deployment. 

You don’t have to take our word for any of it. Before you commit, your engineers can prove Oradian’s architecture and performance in a sandbox that mirrors production, and our implementation teams in your local markets, never outsourced, run the migration with you domain by domain. 

Launch on a product engine so you can modernise at your own pace. 

You don’t need to choose between a legacy core that caps your growth and a replacement project that risks the bank. Run a modern core beside the old one, launch what’s new on it now, and move the rest across when you’re ready. 

Want to launch your next product this quarter and start your migration on your terms? Email vanda.jirasek@oradian.com today to get started.