MockServer

Deploys MockServer into a local Kind cluster: a scriptable mock for any HTTP service, with first-class LLM response mocking — provider-correct OpenAI/Anthropic/Bedrock completions, token-by-token SSE streaming, configurable usage tokens, and failure simulation (429 quotas, mid-stream truncation, malformed chunks). Use it when a test needs an upstream that misbehaves in precise, scripted ways.

• Endpoint: http://localhost:31080 from the host, http://mockserver:1080 from inside the cluster. Expectations and the mocked routes share the same port.
• Web dashboard: http://localhost:31080/mockserver/dashboard — live view of received requests and active expectations.
• Nothing is mocked until you say so: tests create expectations over the REST API and reset them between scenarios.

Install gck#

go install github.com/gravitee-io-labs/gck@latest

For other installation methods, see Installation .

Usage#

Create#

gck create --from mockserver/standalone

Cleanup#

gck delete

Quick Start#

Mock an OpenAI-compatible chat endpoint with one expectation:

curl -s -X PUT http://localhost:31080/mockserver/expectation \
  -H 'Content-Type: application/json' \
  -d '{"httpRequest":{"method":"POST","path":"/v1/chat/completions"},"httpLlmResponse":{"provider":"OPENAI","model":"gpt-4o","completion":{"text":"canned answer","usage":{"inputTokens":12,"outputTokens":8}}}}'

Then call it like a provider:

curl -s http://localhost:31080/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{"model":"gpt-4o","messages":[{"role":"user","content":"hello"}]}'

Add "streaming": true (and optionally streamingPhysics with a seed, tokens-per-second and jitter) inside completion to serve token-by-token SSE with a final usage chunk and data: [DONE]. Plain httpResponse expectations, request verification, and OpenAPI-driven mocks work the same way — see the MockServer documentation and LLM response mocking .

Reset everything between test scenarios:

curl -s -X PUT http://localhost:31080/mockserver/reset

Testing something that fronts several upstreams? Compose this context with the deterministic LLM simulator:

gck create --from llm-d/inference-sim --from mockserver/standalone