Executive summary
Varnish is a programmable reverse-proxy and edge caching engine that helps enterprise financial platform teams to replace inflexible legacy CMS caching layers, deploy granular edge invalidation, and unify distributed CDN configurations for skyrocketing edge cache hit rates to 95%, slashing infrastructure egress costs, and accelerating developer deployment cycles from days to hours.
Managing a sprawling digital footprint is an operational hurdle for any enterprise. But for major global banking and investment institutions, that footprint is compounded by compliance mandates, strict data privacy controls, and a complex matrix of public websites, authenticated customer portals, and internal backend systems.
For one leading European financial institution, managing this massive volume of content on aging infrastructure had become a direct bottleneck to performance, flexibility, and cost efficiency.
Finding flexibility without Adobe Dispatcher
The bank’s primary challenge centered around traffic management and scalable content delivery. They were relying on Adobe Dispatcher, the built-in caching and load-balancing engine for the Adobe Experience Manager (AEM) CMS, to handle their immense traffic volume.
However, the platform engineering team ran into an uphill battle. Adobe Dispatcher operates on rigid, standard caching and invalidation rules. While sufficient for basic corporate websites, it lacked the granularity and custom programmability needed to support custom financial cache policies, secure user sessions, and rapid content updates.
Furthermore, configuring Dispatcher required highly specialized, opaque knowledge. The bank needed a flexible architecture that could sit in front of AEM, handle complex edge logic natively, and give their engineers total control. That search led them to Varnish Enterprise.
Redesigned for speed and efficiency
Transitioning core financial infrastructure to a new technology layer frequently triggers internal resistance. To mitigate risk, Varnish engineers worked directly alongside the bank’s platform team to architect a seamless migration.
Varnish Enterprise completely replaced Adobe Dispatcher. Instead of wrestling with rigid configuration files, the bank’s engineers leveraged the C-based Varnish Configuration Language (VCL) to program custom routing and caching rules.
Because VCL allows complex edge logic to execute directly at the delivery layer, the bank achieved a massive engineering win: they replaced their entire legacy caching architecture without changing a single line of backend code.
The switch instantly unlocked substantial efficiency, security, and redundancy gains:
- Extreme caching efficiency: Even under heavy traffic loads, Varnish operated effortlessly, consuming less than 10% CPU capacity.
- Hardened perimeter security: The team used VCL to instantly implement advanced backend shielding, strict cookie handling, and isolated user-data protection.
- Zero-downtime redundancy: If an origin server or peer cache failed, Varnish automatically served content from an alternate node, allowing the team to conduct routine system maintenance without a second of customer service disruption.
The next phase of Varnish: performance at the edge
With Varnish successfully managing the core application logic, the bank focused on its next objective: maximizing the efficiency of its global Content Delivery Network (Akamai).
Before implementing Varnish, the bank’s global edge cache hit rate hovered between a lackluster 50% and 65%. This meant up to half of all global user requests were missing the edge entirely and traveling all the way back to the bank's core origin servers, driving up infrastructure stress and triggering significant network egress costs.
To solve this, the bank introduced a multi-tier caching strategy using Varnish Enterprise and the Akamai Connector for Varnish:
-
Edge-Side Invalidation: The bank utilized the
s-maxagecache control header. This instructed end-user browsers to store content for only 60 seconds, while telling the Akamai CDN edge to safely hold the same content for 14 days. -
Instant Cache Clearing: When content changed, Varnish executed instantaneous edge-side invalidations, purging stale objects across the network in milliseconds.
Because network traffic flowing between CDN edge servers and the backend carries high variable costs, while edge-to-client delivery does not, this optimization directly slashed the bank's multi-cloud infrastructure and data transfer bills.
Sustainable content delivery solutions for the future
By unifying their delivery architecture under Varnish Enterprise, the bank eliminated duplicative configurations and retired Adobe Dispatcher entirely. This modernization yielded long-term strategic advantages across the organization:
- Accelerated Time-to-Market: Infrastructure teams can now build, test, and deploy complex edge routing solutions in hours rather than days or weeks.
- Unmatched System Agility: In the event of a system update or unexpected failure, configuration hot-reloads and cache restarts take Varnish seconds to execute, compared to the 30+ minutes typically required by global CDNs.
- Continuous Extensibility: Beyond standard caching, the engineering team routinely uses Varnish as an architectural Swiss Army Knife to gracefully handle 404/500 error pages, integrate third-party APIs, protect customer metadata, and patch mobile deep-linking issues on the fly.
“The more familiar we become with Varnish, the more we realize we can use it for. Whether it is 404 and 500 page errors, third-party solution integration and protecting user data, or finding a quick workaround for mobile deep linking issues, Varnish continues to offer viable, sustainable solutions that will carry us into the future.”
Want to learn more? Get in touch to find out how we can help you deliver better traffic management and speed, even during peaks.
