Case Study: Behind the scenes of CSSC’s seamless migration of 170,000 records

CSSC Sports & Leisure is a UK non-profit with more than 170,000 members, giving civil service and public sector staff access to experiences, benefits and perks, including discounted tickets for sports, cultural events, and heritage sites across 1,500 locations. 

With members booking everything from English Heritage to the Royal Botanic Gardens at Kew, CSSC’s operations depend on reliable digital infrastructure.

When its legacy platform reached its limits, CSSC partnered with Nuweb to migrate 170,000 records, live event data, and critical integrations onto a new system. 

For CSSC, this wasn’t just a technical project - it was about trust.

Even the smallest disruption would have risked member confidence and undermined years of credibility.

The challenge for Nuweb was to deliver the transition without downtime, preserving trust with members while building a scalable foundation for future growth.

The migration had to deliver meaningful improvements - tighter integrations, improved admin workflows, and a stronger infrastructure for long-term growth.

This translated into four clear objectives: 

• CSSC only wanted  to migrate future events to keep the process lean, while protecting the 16,100 purchased tickets already in play.

• Preserve all 170,000 membership identifiers and SSO logins without interruption.

• Ensure seamless integration with systems such as payments and APIs.

• Deliver a system that was immediately ready for organisers and administrators to use.

The project also required a robust test plan with rollback options and a cutover process that delivered immediate stability.

Nuweb adopted a selective import strategy designed to focus only on data that mattered for CSSC’s ongoing operations. 

Future events were migrated, reducing risk and complexity, while membership numbers and SSO identifiers were carried over intact to protect every user’s login experience.

The timeline was phased. A bulk data transfer was completed the day before go-live, followed by a final synchronisation at 9am on launch day to capture late purchases and signups. 

This “mop-up” process ensured that no sales activity was lost. At the point of cutover, 16,100 purchased tickets, 1,100 guest list signups, and 170,000 membership records were successfully transferred.

To preserve the complexity of CSSC’s setup, Nuweb transformed every layer of data into a modern schema. This included:

• Visibility groups and user role mapping

• Venue data enriched with geolocation precision

• Event metadata and capacity management

• Complex sale item hierarchies

• Order history with full customer attribution

• Custom frameworks for data capture and reporting

Each element was mapped and validated to maintain consistency with the original records.

CSSC’s product and operations teams worked closely with Nuweb engineers, product managers, and QA specialists. 

Third-party vendors including Barclays (payments) and Microsoft Azure (SSO) were active participants in the process. Regular stakeholder updates, daily alignment meetings, and joint testing sessions ensured all parties moved in step.

Risk management was treated as central to the migration. 

Nuweb and CSSC ran comprehensive user acceptance testing (UAT) cycles and end-to-end validation across systems. 

Shadow environments provided live benchmarks, allowing the teams to validate outputs in real time. Rollback measures were defined at every stage, with complete reversion capability if required.

Incremental validation safeguarded data integrity at every stage of migration, while parallel testing provided a ready fallback.

Timeline buffers absorbed vendor delays, and steady communication kept stakeholders aligned.

CSSC’s platform had to remain connected to the systems members and organisers relied on every day - from logins to payments to the custom-built website frontend. That meant each integration had to be migrated with absolute precision, tested in parallel, and cut over without disruption.

Several integrations were mission-critical:

• Azure AD SSO - providing seamless login for over 170,000 members.

• Event Discovery API - powering CSSC’s custom frontend.

• Member Data API - keeping systems in sync in real time.

• Barclays EPDQ - new payment gateway integration.

• Domains and Redirects - ensuring continuity between CSSC and the Nuweb ticketshop.

The cutover plan was built around these integrations. Bulk migration was completed the day before, with a final synchronisation at 9am on launch morning to capture late activity. 

Once complete, all integrations - SSO, APIs, payments, and domains - were switched over together, monitored in real time, and confirmed stable. Rollback measures were defined but never required.

This was a technically complex migration, but the challenges were expected and managed proactively. 

The main challenge was scale: tens of thousands of live records, many interdependent, all of which had to be transformed into a new schema without losing relationships between members, tickets, and events. Phased imports and integrity checks at each stage ensured accuracy.

At the same time, bookings didn’t stop. Members continued purchasing tickets and joining guest lists right up to launch. A final synchronisation on the morning of cutover ensured no orders were lost.

The migration also required tight coordination between multiple vendors. Payments through Barclays, authentication via Azure, and CSSC’s custom frontend all had to transition at the same time. Joint testing cycles and clear communication channels kept everyone aligned.

Even unexpected details, such as unsupported characters in legacy tags, were addressed through schema adjustments and validation tools. By combining careful preparation with incremental validation, these issues were resolved before they could impact the migration.

The migration was invisible to members, which was exactly the goal. 

More than 170,000 users retained uninterrupted access through SSO, while administrators gained faster search capabilities and improved workflows from day one.

More importantly, the migration laid the foundation for years of growth. Since moving onto Nuweb’s infrastructure, CSSC has scaled its programme across thousands of events, introduced new benefits for members, and expanded its digital ecosystem without facing the limitations of the legacy system.

What started as a risk-managed migration became the launchpad for long-term innovation.

Looking back, what stands out isn’t just the code we shipped or the integrations we wired together - it’s the trust we preserved. Over 170,000 members carried on booking as if nothing had changed. That’s what a migration should feel like.

This project also proved that migrations don’t have to be painful. Legacy systems don’t have to trap organisations, and scale doesn’t have to come at the expense of confidence. With the right engineering mindset, close partnership, and obsessive focus on the end user, transitions like this can unlock more than they risk.

The key lessons are clear: validate third-party readiness early, benchmark every stage of the process, treat integration testing as essential, and always plan for final synchronisation windows. Above all, migrations must be fully project-managed - from risk planning to vendor alignment - if they are to deliver seamless transitions across multiple systems.

The result was not only a successful migration, but a stronger foundation for CSSC to continue expanding its member offering at scale.