Ariadne vs WunderGraph Cosmo

Ariadne is an open-source Python library for building GraphQL APIs with a schema-first design. Developers describe an API using GraphQL Schema Definition Language and connect schema fields to application logic with resolver functions. The server supports asynchronous and synchronous query execution and can be served through WSGI or ASGI apps. The project describes interoperability with web frameworks and includes a Django integration example. Ariadne Codegen creates a typed Python client and Pydantic models from a GraphQL schema and operations; generated client results are validated against those models at runtime. An optional SQLAlchemy 2.0 integration supports synchronous sessions in WSGI and ASGI, while AsyncSession is limited to ASGI and has a documented limitation involving sibling root fields. Ariadne implements the GraphQL multipart request specification for uploads. Its default Upload scalar is write-only and supports values passed through variables. Security documentation discusses denial-of-service and credential-leakage risks and gives mitigation guidance. Ariadne is self-hosted and free, and the site lists Linux, web, and API platforms.

WunderGraph Cosmo is an open-source GraphQL Federation platform for platform teams, offering schema checks, guardrails and observability. It unifies GraphQL, REST, gRPC and Kafka in a federated graph and supports Apollo Federation versions 1 and 2 across existing GraphQL services. Cosmo Router is a Go-based, Apache 2.0-licensed router and gateway. Teams can deploy it with Docker, Kubernetes or an AWS Lambda-optimized binary, or use WunderGraph’s managed service. The Schema Registry checks composition, breaking changes, client traffic and linting. Subscriptions work over WebSockets and Server-Sent Events, and event-driven subscriptions can use Kafka, NATS, SQS or RabbitMQ. Cosmo Streams supports Kafka, NATS including JetStream, and Redis. Observability includes OpenTelemetry tracing and Prometheus metrics, which can be exported to compatible backends. The free Developer plan includes one federated graph, 10M requests/month, 10 subgraphs, one team member and seven-day retention. Launch costs $499 a month; Scale costs $3,499 a month. Enterprise pricing is custom. Managed plans include SOC 2 and HIPAA compliance; the site also identifies ISO 27001 certification.