■ API Simulation

Real API simulation: state, chaos, and real traffic — not just a fixed JSON.

A static mock only tests response shape. Real simulation also tests how your system behaves under state, failure, and the actual traffic your API will receive.

Simulate my first API → See how it works ↓

The limit of a static mock

A fixed response never changes between calls — doesn't test stateful flows (create → list → update)
Never fails, never lags — your system is never tested against a real, unstable API's behavior
Writing a mock from scratch off an OpenAPI spec is repetitive manual work
Once the mock exists, nobody notices when the real API changes and it goes stale

With httpdrop simulation

Automatic stateful CRUD: real state persisted across calls, no code needed
Per-route Chaos Mode: injects configurable latency and error rate to test resilience
Design-first: generates Mock Rules from an OpenAPI/Swagger spec
Real traffic capture with automatic generalization into a rule set
Drift Alerts: warns when the mock diverges from the original contract/spec
MCP tools for AI-assisted mock generation and validation, straight from your editor

How it works

Start from the right pillar

API Mocking for a simple contract, Chaos Testing for resilience, Webhook Testing for async events.

Add state

Automatic CRUD turns any path into a resource with real persistence.

Add chaos

Configure latency and error rate per route, without touching your system's code.

Or start from an existing spec

Import OpenAPI/Swagger and get Mock Rules generated automatically.

Keep it under control

Drift Alerts warn you when the real API has moved on and the mock is stale.

Example — fault injection on a route

// Chaos Mode on GET /orders/{id}
{
  "latencyMs": 800,        // simulated delay
  "errorRate": 0.15,       // 15% of calls return an error
  "errorStatus": 503
}

What httpdrop simulation is

Behavior, not just shape: state, failure, and drift are all part of the simulation
A common ground for the other 4 pillars — mocking, webhooks, sandbox and chaos connect here

What it isn't

Not an identical copy of your real API — it's a simulation faithful enough to test contract and behavior
Not a load-testing tool against production infrastructure

Use cases

Resilience engineering (SRE)

Test how your system reacts to latency and errors before it happens in production.

Contract-first teams

Generate the mock straight from an OpenAPI spec and keep it in sync with Drift Alerts.

AI agents and automation

MCP tools let an AI agent generate and validate mocks from captured real traffic.

FAQ

Do I need to set up all of this to get started?

No — start with a simple Mock Rule and add state, chaos, or OpenAPI generation when you need it.

What's a Drift Alert?

An automatic warning when your real API's behavior diverges from what the mock simulates — so you're not relying on a stale contract.

Can I use this with an AI agent?

Yes — httpdrop's MCP tools let you generate, validate, and generalize mocks straight from your editor or agent.

Related resources

Start simulating your API for real

State, chaos, spec, and real traffic — all in one platform.

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