Beeceptor vs MockServer

Beeceptor is a developer-focused API simulation platform for mocking services, virtualizing them, testing contracts, and simulating failures. It supports HTTP, HTTPS, HTTP/2, mTLS, REST/OpenAPI, SOAP, GraphQL, and gRPC. Users can build no-code mocks with request-matching rules and set response status codes, headers, and bodies. Uploading an OpenAPI specification can create a populated mock server with AI-generated data. Beeceptor can proxy requests to live backends, record traffic, and switch to mock behavior when a backend is unavailable. Latency, timeouts, and errors can be simulated to check client resilience. Its CLI exposes a localhost service through a public HTTPS URL and runs on Windows, macOS, and Linux. Management APIs support mock-server configuration, while MCP connectivity supports AI agents including Claude and Cursor. API Connections store OAuth credentials and generate tokens for outbound requests. Beeceptor says it is SOC 2 Type II audited, adheres to ISO 27001, and complies with GDPR; it also says data is encrypted in transit and at rest. The free plan has public endpoints, a 1 MB request payload limit, and cleanup rules for unclaimed endpoints.

MockServer is a free, self-hosted tool for mocking and proxying HTTP, HTTPS, and gRPC services during isolated testing. It can verify requests as well as stand in for services. Teams can generate mocks and validate traffic against OpenAPI or Swagger contracts, or import recorded sessions from browser HAR files and Postman collections. Beyond HTTP services, it can mock gRPC, AsyncAPI brokers such as Kafka, MQTT, and AMQP, and OAuth2/OIDC providers. Its protocol coverage includes HTTP/1.1, HTTP/2, HTTPS, SOCKS, and experimental HTTP/3, which uses a separate UDP port. For fault-oriented testing, it can add latency, errors, dropped connections, and malformed responses to mocked or proxied traffic. Deployment options include Docker, an executable JAR, Helm/Kubernetes, Testcontainers, Homebrew, and a JVM-less bundle. A web dashboard displays logs, expectations, and recorded traffic; Prometheus metrics and OpenTelemetry tracing are available for shared environments. Each instance includes an MCP server at /mockserver/mcp. The /mockserver/status and /mockserver/ready probes remain reachable without authentication or authorization.