Amplitude

Lightweight, dependency-free, in-memory Amplitude HTTP API v2 fake for testing code that uses the real @amplitude/analytics-node SDK (and the language-agnostic Amplitude HTTP V2 / Batch / Identify APIs).

Default port: 4809

Quick start

import { AmplitudeServer } from "./services/amplitude/src/server.js";

const server = new AmplitudeServer(4809);
await server.start();
// ... run your app/tests ...
await server.stop();

Point the real @amplitude/analytics-node client at it via serverUrl:

import { init, track } from "@amplitude/analytics-node";

init("parlel", { serverUrl: "http://127.0.0.1:4809/2/httpapi" });
track("Signup", { plan: "pro" }, { user_id: "user-1" });

Every ingested event is held in memory and inspectable via /__parlel/*.

Implemented operations

Authentication is via api_key supplied in the request body (matching the HTTP V2 API).

Ingestion

POST /2/httpapi — HTTP API V2 event ingest. Returns { code: 200, events_ingested, payload_size_bytes, server_upload_time }.
POST /batch — Batch Event Upload API (same handling/shape).
POST /identify — Identify API; identification is a JSON-encoded array or object. Returns { code: 200, identifies_ingested, server_upload_time }.

Query

GET|POST /api/2/usersearch — dashboard user search (?user= or { user }). Returns { matches: [...], type }.

Service & inspection operations (parlel extensions)

GET / — service metadata.
GET /health — health check ({ status: "ok" }).
POST /__parlel/reset — reset all state.
GET /__parlel/events — list captured events.
GET /__parlel/users — list identified users.
DELETE /__parlel/events — clear captured events.
OPTIONS * — CORS preflight (204).

Access via MCP / preview URL

In a parlel pool, the service is reachable at its preview URL (host/port shown by the pool); set serverUrl to <preview-url>/2/httpapi. Through the parlel MCP server, the ingest/identify/usersearch routes are exposed as a tool surface so an AI agent can drive ingestion and inspect what landed.

Surface coverage

This emulator faithfully replicates the API surface most application code and agents exercise. Anything below the supported lines is either an intentional design choice for a fast, zero-cost local emulator (✓ By design) or a candidate for a future release (⟳ Roadmap) — never a silent inaccuracy.

Legend: ✅ fully supported · ◐ accepted (stored, not strictly enforced) · ✓ by design · ⟳ on the roadmap.

Feature	Status
`/2/httpapi` event ingest (v2 shape)	✅ Supported
`/batch` ingest	✅ Supported
`/identify` user properties	✅ Supported
`/api/2/usersearch` lookup	✅ Supported
Captured-event inspection	✅ Supported (parlel extension)
Real charts / behavioral cohorts	⟳ Roadmap
Throttling / `429` flow control	✓ By design — Never throttles — local tests run at full speed, zero cost
`api_key` validity check	✓ By design — Intentional for a local, zero-cost test emulator

Manifest

See services/amplitude/manifest.json:

name: amplitude, image: parlel/amplitude:1.0
port: 4809, protocol: http, healthcheck: /health, startup ≈ 100ms
env: AMPLITUDE_API_KEY, AMPLITUDE_SECRET_KEY, AMPLITUDE_HOST

Configuration — `test.env`

Copy these into your test.env (used by the bridge sidecar flow). Tokens are Parlel's seeded test credentials — any non-empty value is accepted by the emulator, so you rarely need to change them. Swap in real credentials only when pointing at the live service in prod.env.

AMPLITUDE_API_KEY=parlel
AMPLITUDE_SECRET_KEY=parlel-secret
AMPLITUDE_HOST=http://parlel-bridge:4809
AMPLITUDE_BASE_URL=http://parlel-bridge:4809