Open-Source GraphQL Federation for Platform Teams

As more teams ship subgraphs, federation becomes brittle and harder to govern.
WunderGraph Cosmo helps platform teams evolve federated APIs safely with built-in schema checks, guardrails, and deep observability.

GraphQL Federation that just works.

Get Started For Free in 3 minutes Read the docs

Built for every use case

Modern API architectures are multi-protocol.
Cosmo unifies them under a single federated graph.

Unify API Infrastructure Across GraphQL, REST, gRPC, and Kafka

Fragmented contracts and duplicated routing logic slow teams down. Cosmo unifies routing, schemas, and observability into one shared execution model.
Open source. Language-agnostic.
Built for monoliths, microservices, and federated graphs.

Federation v1 and v2 compatible

Works with all existing GraphQL services. Any framework, any language.

High-Performance Router

Built in Go with native support for authentication, subscriptions, and observability.

Maximized compliance

Deploy fully on-prem or use a hybrid model with a managed control plane and self-hosted routers to meet strict compliance and regulatory requirements.

Powerful CLI

Search schemas and documentation directly from your terminal, including through tools like Cursor.

Migrate from Apollo in one click Talk to Sales

How Cosmo Powers Federation at Scale

Cosmo Streams

Traditional GraphQL subscriptions don't scale in federated systems. Each subgraph must stay connected and coordinated, increasing resource usage and operational overhead.

—

Streams connects your federated graph to event streams like Kafka, NATS, or Redis. The router listens for events and updates subscriptions automatically, keeping subgraphs stateless, efficient, and easier to operate at scale.

Docs

Cosmo Connect

Federation adoption often stalls when backend teams are forced to rewrite services to fit GraphQL.

—

Cosmo Connect lets teams keep their existing backends and languages. It maps GraphQL schema fields to backend gRPC services, so the router handles translation and delivers one unified API to the frontend.

Docs

MCP

Managing a federated graph often requires switching between CLIs, docs, and dashboards just to explore schemas or validate changes.

—

Cosmo MCP Server brings federation workflows into your IDE. It connects Cosmo to tools like Cursor, Windsurf, and VSCode, allowing you to explore schemas and validate configurations directly from your editor. No CLI or context switching required.

Docs

Feature Flags

Shipping schema changes shouldn't break production.

Feature flags let you publish alternate subgraphs that temporarily replace existing ones, route select traffic through preview versions, and compare performance across releases.

Test safely in production without affecting real users, and roll out gradually. Validate changes with real traffic, and ship updates with confidence. See how Acoustic solved this.

See how Acoustic solved this

Monolith to Federation

On The Beach cut latency by tens of milliseconds and scaled to higher traffic with fewer resources after migrating from a monolithic GraphQL API to WunderGraph Cosmo.

Federation and schema management became faster, more reliable, and easier for teams to own, improving developer velocity and reducing infrastructure costs.

Read the full story in the On The Beach case study.

Read the On The Beach case study

Trusted by engineering teams worldwide

$178K

30%

10x

1 Day

10 Days

“With Cosmo, we saved an estimated $178,000 just on building those features. That doesn't even include the cost of maintaining or supporting them long term.”

Karol Krogulec

Senior Engineering Manager, Acoustic

$178K

Saved

“Our infrastructure costs went from $14,000 with our previous provider down to $9,750 with Cosmo, even with some extra infra costs.”

Tim Caplis

Principal Software Engineer, SoundCloud

30%

Lower Costs

“We have experienced significant performance enhancements for our most complex queries since switching from Apollo to Cosmo. The query planning in Cosmo is more advanced and intelligently optimized.”

Fredrik Wärnsberg

Vice President of Engineering, Soundtrack Your Brand

Faster Queries

“Now, Cosmo presents all the relevant stats—how many queries run, their response times, and key performance metrics—making it much easier to communicate what's happening under the hood. This improved observability not only enhances request tracing but also helps teams understand how their queries run in a federated system. Ultimately, Cosmo has made it much easier for teams to buy into Federation.”

Stephen Wootten

Senior Software Engineer, On The Beach

10x

Better Observability

“Cosmo's Advanced Request Tracing is instrumental to further optimize our subgraphs and enhance query performance for our customers. We're impressed with their swift response times and ease of communication.”

Jack

Head of platform, Tailor

Faster Delivery

“A solution that is scalable and PCI compliant. Migrating to cosmo is super intuitive and took just a day to reconfigure everything.”

Tyler Hawkins

Backend Architect, Travelpass Group

1 Day

Migration

“We learned about WunderGraph Cosmo and deployed it into production in about ten days. I highly recommend WunderGraph Cosmo; they helped us pivot quickly when we needed a solution ASAP! Everything now is working perfectly.”

José Rose

Senior Developer, PemPem

10 Days

To Production

“We are switching to NATS since there is a huge need for asynchronous patterns and event sourcing. GraphQL subscriptions was a must for this. Implementation of EDFS was easy. When we are talking on our discord, they are there and they know what they are talking about. It really is a pleasure to work with WunderGraph.”