Acoustic saves $178K in engineering costs with WunderGraph Cosmo

By moving to Cosmo, Acoustic saved nearly $178,000 in engineering effort. What once meant brittle builds, Rust plugins, and CI-heavy rollbacks is now handled by a faster, schema-aware router .

Acoustic is a marketing and customer engagement platform that helps global brands create personalized, data-driven experiences across email, mobile, SMS, and social channels. Serving more than 3,500 brands, including Fortune 500 companies , the company provides an integrated marketing cloud with AI-powered tools for campaign management, personalization, analytics, and customer journey optimization.

Maintaining Acoustic’s GraphQL gateway was on track to consume $178,000 in engineering time. The system had grown too complex to evolve efficiently.

Their marketing tech platform powered big brands, but schema conflicts caused regular deployment issues, and rollbacks required coordination with the DevOps team. The Rust-based router took up to 30 minutes to build, and every subgraph change triggered a full supergraph rebuild.

What had worked in the past was now dragging down development. Fixing it meant building out missing infrastructure around the GraphQL layer; features like authentication, rate limiting, and public/private endpoint separation that required custom workarounds just to keep things running.

They needed an exit before the maintenance cost outweighed the value.

The team’s gateway stack had grown complex. Authentication lived in Lambdas. All the subgraphs were managed in a single GitHub repository, with no schema registry or UI to inspect changes.

Understanding how changes would affect the graph could mean digging through 10,000+ lines of code. Custom features like authentication had been written in Rust, which slowed development and limited who could contribute. Rollbacks weren’t simple; they required CI support and often took hours to resolve. As Karol Krogulec, Senior Engineering Manager at Acoustic, explained, "With Rust, we would still be writing plugins instead of writing code."

That friction added up fast.

Rate limiting, usage tiers, auth enforcement, and endpoint filtering were all missing. Building them in Rust would have eaten months of engineering time and tied the team even tighter to a system they already wanted to escape.

Three priorities stood out.

First, they needed better separation between public and private APIs, with built-in rate limiting and throttling. Their platform served multiple customer tiers, so this was non-negotiable.

Second, they needed to move faster. Router builds took 30 minutes, and schema inspection happened through GitHub. Developing in Rust was slowing down engineers while simultaneously limiting who could contribute. Acoustic needed visibility, developer-friendly tooling, and a real UI.

Third, they needed a pricing model that fit their business. Rigid licensing models didn’t match their unpredictable usage patterns or team structure. Cosmo’s support-based model gave them the flexibility to scale traffic and services without tracking headcount or renegotiating contracts.

That flexibility mattered. It let the platform team stay focused on architecture—not approvals—and kept business decisions aligned with engineering reality.

An engineer on the team suggested trying WunderGraph Cosmo. It was open source, with the core Federation features they’d been piecing together themselves. The docs were solid, the setup felt clean, and running it on their own infrastructure gave them full control from day one.

What surprised the team was how smooth the early testing felt. Pre-prod trials showed real improvements to developer UX, not just rough parity with their existing system, but a noticeably better experience.

The open-source and enterprise offerings shared the same foundations. That gave Acoustic confidence that they weren’t locking themselves into another brittle vendor setup.

They didn’t rush. Acoustic ran Cosmo in pre-production for about a month, using the same schema and subgraphs as their legacy system. As Kira Shatskyi explained, “The migration was just updating the DNS record from the old router to the Cosmo Router.”

There were edge cases and bugs early on, but support landed fast.

When the team asked about support for the @exclude directive, it was live within three weeks. Jens Neuse even joined the Slack thread. As Karol Krogulec recalled, “the issue was quickly addressed by the Cosmo team, with the CEO himself writing the code, and we received a PR after just a couple of hours.”

Cosmo helped them cut complexity fast. They no longer needed Rust plugins, auth Lambdas, Jenkins pipelines, or manual CI rollbacks. Platform engineers can now view the full schema visually, eliminating the need to grep through thousands of lines of GraphQL.

"Every subgraph change used to require building and deploying the entire supergraph," said Stefan Hepper, Distinguished Architect from Acoustic. "It was brittle—failures could cost us a full day just to reconcile. With Cosmo, all of that went away."

The Go-based router was fast and familiar. Cosmo’s support for @include and @exclude made routing patterns cleaner and more maintainable, especially for legacy and client-specific APIs.

Cosmo didn’t just improve performance, it restored confidence.

The federated graph was no longer a daily concern—it faded into the background.

The partnership was just as important as the platform. WunderGraph’s support team answered quickly. Roadmap discussions turned into working features in weeks. Acoustic didn’t just adopt a new tool; they helped shape it.

They can now run customer-specific APIs on isolated routers. Endpoints are taggable and access is controlled; each client sees only what they’re supposed to. Schema rollbacks no longer require CI pipelines; they’re faster, simpler, and safer.

These weren’t bonus features. They were blockers—and now they’re gone.

Cosmo’s route isolation lets Acoustic ship tailored interfaces without compromising their public APIs.

As Stefan Hepper explained, “the ability to tag methods and deploy them to specific routers—public, private, or for a single client—let us build a one-off interface for a customer without touching our public APIs.”

Acoustic’s advice to other platform teams: don’t just validate Federation. Validate everything. Can you roll back easily? Is auth built in? Can you inspect diffs before a schema hits production?

With Cosmo, Acoustic didn’t just sidestep $178K in engineering costs. They got their time back. They got simplicity. And they got a graph that just works.

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