Content
# aimock [](https://github.com/CopilotKit/aimock/actions/workflows/test-unit.yml) [](https://github.com/CopilotKit/aimock/actions/workflows/test-drift.yml) [](https://www.npmjs.com/package/@copilotkit/aimock)
https://github.com/user-attachments/assets/76815122-574a-48e1-b275-edae0a014667
Mock infrastructure for AI application testing — LLM APIs, image generation, image editing, text-to-speech, transcription, audio translation, audio generation, video generation, embeddings, MCP tools, A2A agents, AG-UI event streams, vector databases, search, rerank, and moderation. One package, one port, zero dependencies.
## Quick Start
```bash
npm install @copilotkit/aimock
```
```typescript
// The class is still named `LLMock` for back-compat after the v1.7.0 package
// rename from `@copilotkit/llmock` to `@copilotkit/aimock`.
import { LLMock } from "@copilotkit/aimock";
const mock = new LLMock({ port: 0 });
mock.onMessage("hello", { content: "Hi there!" });
await mock.start();
// Set env BEFORE importing/constructing the OpenAI (or other provider) client.
// Many SDKs cache the base URL at construction time — if the client is built
// before these are set, it will talk to the real API (surprise bills) instead
// of aimock.
process.env.OPENAI_BASE_URL = `${mock.url}/v1`;
process.env.OPENAI_API_KEY = "mock"; // SDK requires a value, even when base URL is mocked
// ... run your tests ...
await mock.stop();
```
## The aimock Suite
aimock mocks everything your AI app talks to:
| Tool | What it mocks | Docs |
| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------- |
| **LLMock** | OpenAI (Chat/Responses/Realtime GA+Beta), Claude, Gemini (REST/Live/Interactions/Embeddings), Bedrock, Azure, Vertex AI, Ollama (chat/embeddings), Cohere (chat/embed), ElevenLabs TTS | [Providers](https://aimock.copilotkit.dev/docs) |
| **MCPMock** | MCP tools, resources, prompts with session management | [MCP](https://aimock.copilotkit.dev/mcp-mock) |
| **A2AMock** | Agent-to-agent protocol with SSE streaming | [A2A](https://aimock.copilotkit.dev/a2a-mock) |
| **AGUIMock** | AG-UI agent-to-UI event streams for frontend testing | [AG-UI](https://aimock.copilotkit.dev/agui-mock) |
| **VectorMock** | Pinecone, Qdrant, ChromaDB compatible endpoints | [Vector](https://aimock.copilotkit.dev/vector-mock) |
| **Services** | Tavily search, Cohere rerank, OpenAI moderation, ElevenLabs TTS | [Services](https://aimock.copilotkit.dev/services) |
Run them all on one port with `npx @copilotkit/aimock --config aimock.json`, or use the programmatic API to compose exactly what you need.
## Features
- **[Record & Replay](https://aimock.copilotkit.dev/record-replay)** — Proxy real APIs, save as fixtures, replay deterministically forever
- **Timing-aware recording and replay** — Recorded fixtures capture per-frame arrival timestamps; replay uses recorded timings for approximate timing reproduction based on recorded TTFT and inter-frame cadence (replay chunk count may differ from recording — TTFT and average pace are preserved, not per-token fidelity) with configurable `--replay-speed` multiplier
- **[Multi-turn Conversations](https://aimock.copilotkit.dev/multi-turn)** — Record and replay multi-turn traces with tool rounds; match distinct turns via `turnIndex`, `hasToolResult`, `toolCallId`, `sequenceIndex`, `systemMessage` (gate on host-supplied agent context), or custom predicates
- **[14 LLM Providers](https://aimock.copilotkit.dev/docs)** — OpenAI Chat, OpenAI Responses, OpenAI Realtime (GA + Beta shim), Claude, Gemini (REST + embedContent), Gemini Live, Gemini Interactions, Azure, Bedrock, Vertex AI, Ollama (chat + embeddings), Cohere (chat + embed), ElevenLabs TTS — full streaming support
- **Multimedia APIs** — [image generation](https://aimock.copilotkit.dev/images) (DALL-E, Imagen), [image editing](https://aimock.copilotkit.dev/images) (/v1/images/edits), [text-to-speech](https://aimock.copilotkit.dev/speech) (OpenAI + ElevenLabs), [audio transcription](https://aimock.copilotkit.dev/transcription), [audio translation](https://aimock.copilotkit.dev/transcription) (/v1/audio/translations), [video generation](https://aimock.copilotkit.dev/video), [fal.ai](https://aimock.copilotkit.dev/fal-ai) (image / video / audio with queue lifecycle)
- **[MCP](https://aimock.copilotkit.dev/mcp-mock) / [A2A](https://aimock.copilotkit.dev/a2a-mock) / [AG-UI](https://aimock.copilotkit.dev/agui-mock) / [Vector](https://aimock.copilotkit.dev/vector-mock)** — Mock every protocol your AI agents use
- **[Chaos Testing](https://aimock.copilotkit.dev/chaos-testing)** — 500 errors, malformed JSON, mid-stream disconnects at any probability
- **Per-Request Strict Mode** — `X-AIMock-Strict` header overrides the server-level `--strict` flag per request (`true`/`1` = strict, `false`/`0` = lenient)
- **Context-Based Fixture Routing** — `X-AIMock-Context` header scopes fixtures per integration; fixtures with `match.context` only match requests carrying that context, fixtures without it remain shared
- **[Drift Detection](https://aimock.copilotkit.dev/drift-detection)** — Daily CI validation against real APIs
- **[Streaming Physics](https://aimock.copilotkit.dev/streaming-physics)** — Configurable `ttft`, `tps`, and `jitter`
- **[WebSocket APIs](https://aimock.copilotkit.dev/websocket)** — OpenAI Realtime (GA protocol with models: gpt-realtime, gpt-realtime-2, gpt-realtime-1.5, gpt-realtime-mini; transcription/translation via gpt-4o-transcribe, gpt-4o-mini-transcribe, whisper-1; image input; commentary phase), Responses WS, Gemini Live
- **[Prometheus Metrics](https://aimock.copilotkit.dev/metrics)** — Request counts, latencies, fixture match rates
- **[Docker + Helm](https://aimock.copilotkit.dev/docker)** — Container image and Helm chart for CI/CD
- **[Vitest & Jest Plugins](https://aimock.copilotkit.dev/test-plugins)** — Zero-config `useAimock()` with auto lifecycle and env patching
- **[Response Overrides](https://aimock.copilotkit.dev/fixtures)** — Control `id`, `model`, `usage`, `finishReason` in fixture responses
- **[Streaming Usage Chunks](https://aimock.copilotkit.dev/streaming-physics)** — `stream_options.include_usage` support emits a final chunk with token counts, matching OpenAI's streaming usage protocol
- **[Rate Limiting Headers](https://aimock.copilotkit.dev/chaos-testing)** — `x-ratelimit-*` headers on every response and `Retry-After` on 429 errors for testing retry/backoff logic
- **Zero dependencies** — Everything from Node.js builtins
## GitHub Action
```yaml
- uses: CopilotKit/aimock@v1
with:
fixtures: ./test/fixtures
- run: npm test
env:
OPENAI_BASE_URL: http://127.0.0.1:4010/v1
```
See the [GitHub Action docs](https://aimock.copilotkit.dev/github-action) for all inputs and examples.
## CLI
```bash
# LLM mocking only
npx -p @copilotkit/aimock llmock -p 4010 -f ./fixtures
# Remote fixtures — load JSON from an HTTPS URL (repeatable)
npx -p @copilotkit/aimock llmock -p 4010 \
-f https://raw.githubusercontent.com/acme/mocks/main/openai.json \
-f ./fixtures/local-overrides.json
# Full suite from config
npx @copilotkit/aimock --config aimock.json
# Record mode: proxy to real APIs, save fixtures
npx -p @copilotkit/aimock llmock --record --provider-openai https://api.openai.com
# Record with extended timeout for reasoning models
npx -p @copilotkit/aimock llmock --record --provider-openai https://api.openai.com \
--body-timeout-ms 180000
# Replay recorded fixtures at 2× speed
npx -p @copilotkit/aimock llmock -p 4010 -f ./fixtures --replay-speed 2
# Convert fixtures from other tools
npx @copilotkit/aimock convert vidaimock ./templates/ ./fixtures/
npx @copilotkit/aimock convert mockllm ./config.yaml ./fixtures/
# Docker
docker run -d -p 4010:4010 -v "$(pwd)/fixtures:/fixtures" ghcr.io/copilotkit/aimock -f /fixtures -h 0.0.0.0
```
> **Note on `llmock` vs `aimock` CLIs.** The `llmock` bin is retained as a compat alias for users of the pre-1.7.0 `@copilotkit/llmock` package. It runs a narrower flag-driven CLI without `--config` or the `convert` subcommand. New projects should use `aimock` (or `npx @copilotkit/aimock`) for full feature support.
### Remote fixture URLs
`--fixtures` accepts `https://` and `http://` URLs pointing at JSON fixture files in addition to filesystem paths, and the flag is repeatable so you can layer remote and local sources in argv order. Fetched fixtures are cached on disk at `~/.cache/aimock/fixtures/<sha256-of-url>/` (honors `$XDG_CACHE_HOME`); when paired with `--validate-on-load`, a fetch failure with a valid cached copy logs a warning and continues — without a cache, the process exits non-zero. HTTP fetches have a 10s timeout and a 50 MB body cap; redirects are rejected fail-loud, so configure your upstream to serve the final URL directly (GitHub raw content URLs already do).
Private and link-local addresses (loopback, RFC1918, CGNAT, cloud metadata, ULA, multicast) are rejected by default to prevent SSRF. For local development or tests that need to hit `127.0.0.1`, opt out with `AIMOCK_ALLOW_PRIVATE_URLS=1`. Tarball and zip URL support is intentionally deferred.
## Framework Guides
Test your AI agents with aimock — no API keys, no network calls: [LangChain](https://aimock.copilotkit.dev/integrate-langchain) · [CrewAI](https://aimock.copilotkit.dev/integrate-crewai) · [PydanticAI](https://aimock.copilotkit.dev/integrate-pydanticai) · [LlamaIndex](https://aimock.copilotkit.dev/integrate-llamaindex) · [Mastra](https://aimock.copilotkit.dev/integrate-mastra) · [Google ADK](https://aimock.copilotkit.dev/integrate-adk) · [Microsoft Agent Framework](https://aimock.copilotkit.dev/integrate-maf)
## Switching from other tools?
Step-by-step migration guides: [MSW](https://aimock.copilotkit.dev/migrate-from-msw) · [VidaiMock](https://aimock.copilotkit.dev/migrate-from-vidaimock) · [mock-llm](https://aimock.copilotkit.dev/migrate-from-mock-llm) · [piyook/llm-mock](https://aimock.copilotkit.dev/migrate-from-piyook) · [Python mocks](https://aimock.copilotkit.dev/migrate-from-python-mocks) · [openai-responses](https://aimock.copilotkit.dev/migrate-from-openai-responses) · [Mokksy](https://aimock.copilotkit.dev/migrate-from-mokksy)
## Documentation
**[https://aimock.copilotkit.dev](https://aimock.copilotkit.dev)** · [Example fixtures](https://aimock.copilotkit.dev/examples)
## Real-World Usage
[AG-UI](https://github.com/ag-ui-protocol/ag-ui) uses aimock for its [end-to-end test suite](https://github.com/ag-ui-protocol/ag-ui/tree/main/apps/dojo/e2e), verifying AI agent behavior across LLM providers with [fixture-driven responses](https://github.com/ag-ui-protocol/ag-ui/tree/main/apps/dojo/e2e/fixtures/openai).
## License
MIT
