Developer tools1 sources·Published

Mock LLM API server for developers stress-testing LLM app infrastructure

Teams building LLM-powered apps need to load-test their own gateways, queues, and streaming paths but can't afford to burn real token spend on the provider APIs. They end up hand-rolling mock servers. A drop-in, API-compatible fake LLM endpoint with configurable streaming, latency, errors, and rate limits would let them test infra for free.

Score 781 sourcesConfidence 82%

The problem

When developers stress-test their LLM app infrastructure, hitting the real OpenAI/Claude APIs turns a scalability test into a token-spending test. They currently have to build and maintain their own mocking service from scratch, duplicating effort across every company.

What could be built

A self-hostable or hosted API-compatible mock endpoint for OpenAI/Anthropic that returns deterministic canned responses, simulates streaming, configurable latency/time-to-first-token, token counts, tool calls, 429/5xx errors, and malformed streams—so teams can load-test everything around the model without paying for inference.

Who it's for

Backend/platform engineers at startups building LLM-powered productsSRE and QA teams load-testing chatbot or agent infrastructure

Who is talking1

Related topics

LLM API mockingOpenAIAnthropicload testingdeveloper tooling

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