Instantly local dev loop

Instantly Local Dev Loop

Overview

Set up a local development workflow for Instantly integrations. Instantly provides a mock server at `` for testing without sending real emails or consuming API limits. This skill covers mock server usage, integration testing, and local webhook development.

Prerequisites

• Completed instantly-install-auth setup
• Node.js 18+ with TypeScript
• A separate Instantly API key for dev/test (recommended)

Instructions

Step 1: Configure Dev Environment

// src/config.ts
import "dotenv/config";

interface Config {
  baseUrl: string;
  apiKey: string;
  useMock: boolean;
}

export function getConfig(): Config {
  const useMock = process.env.INSTANTLY_USE_MOCK === "true";
  return {
    baseUrl: useMock
      ? "https://developer.instantly.ai/_mock/api/v2"
      : process.env.INSTANTLY_BASE_URL || "https://api.instantly.ai/api/v2",
    apiKey: process.env.INSTANTLY_API_KEY || "",
    useMock,
  };
}

# .env.development
INSTANTLY_API_KEY=your-dev-api-key
INSTANTLY_BASE_URL=https://api.instantly.ai/api/v2
INSTANTLY_USE_MOCK=true

# .env.production
INSTANTLY_API_KEY=your-prod-api-key
INSTANTLY_BASE_URL=https://api.instantly.ai/api/v2
INSTANTLY_USE_MOCK=false

Step 2: Build a Testable API Client

// src/instantly.ts
import { getConfig } from "./config";

const config = getConfig();

export async function instantly<T = unknown>(
  path: string,
  options: RequestInit = {}
): Promise<T> {
  const url = `${config.baseUrl}${path}`;
  const res = await fetch(url, {
    ...options,
    headers: {
      "Content-Type": "application/json",
      Authorization: `Bearer ${config.apiKey}`,
      ...options.headers,
    },
  });

  if (res.status === 429) {
    const retryAfter = parseInt(res.headers.get("retry-after") || "2", 10);
    console.warn(`Rate limited. Retrying in ${retryAfter}s...`);
    await new Promise((r) => setTimeout(r, retryAfter * 1000));
    return instantly<T>(path, options);
  }

  if (!res.ok) {
    const body = await res.text();
    throw new InstantlyError(res.status, path, body);
  }

  return res.json() as Promise<T>;
}

class InstantlyError extends Error {
  constructor(
    public status: number,
    public path: string,
    public body: string
  ) {
    super(`Instantly API ${status} on ${path}: ${body}`);
    this.name = "InstantlyError";
  }
}

Step 3: Write Integration Tests

// tests/instantly.test.ts
import { describe, it, expect, beforeAll } from "vitest";
import { instantly } from "../src/instantly";

describe("Instantly API Integration", () => {
  it("should list campaigns", async () => {
    const campaigns = await instantly<Array<{ id: string; name: string }>>(
      "/campaigns?limit=5"
    );
    expect(Array.isArray(campaigns)).toBe(true);
  });

  it("should list email accounts", async () => {
    const accounts = await instantly<Array<{ email: string }>>(
      "/accounts?limit=5"
    );
    expect(Array.isArray(accounts)).toBe(true);
  });

  it("should create and delete a lead list", async () => {
    const list = await instantly<{ id: string; name: string }>(
      "/lead-lists",
      {
        method: "POST",
        body: JSON.stringify({ name: `test-list-${Date.now()}` }),
      }
    );
    expect(list.id).toBeDefined();
    expect(list.name).toContain("test-list-");

    // Clean up
    await instantly(`/lead-lists/${list.id}`, { method: "DELETE" });
  });

  it("should handle 401 on bad key", async () => {
    const res = await fetch("https://api.instantly.ai/api/v2/campaigns?limit=1", {
      headers: { Authorization: "Bearer invalid-key" },
    });
    expect(res.status).toBe(401);
  });
});

Step 4: Local Webhook Testing with ngrok

set -euo pipefail
# Start your webhook server locally
# In terminal 1:
npx tsx src/webhook-server.ts  # listens on port 3000

# In terminal 2 — expose with ngrok:
ngrok http 3000

# Register the ngrok URL as a webhook
curl -X POST https://api.instantly.ai/api/v2/webhooks \
  -H "Authorization: Bearer $INSTANTLY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Local Dev Webhook",
    "target_hook_url": "https://abc123.ngrok.io/webhooks/instantly",
    "event_type": "all_events"
  }'

// src/webhook-server.ts — minimal local webhook receiver
import express from "express";

const app = express();
app.use(express.json());

app.post("/webhooks/instantly", (req, res) => {
  console.log("Webhook received:", JSON.stringify(req.body, null, 2));
  res.status(200).json({ received: true });
});

app.listen(3000, () => console.log("Webhook server on http://localhost:3000"));

Step 5: Test Webhook Delivery

// After registering the webhook, test it via API
async function testWebhook(webhookId: string) {
  await instantly(`/webhooks/${webhookId}/test`, { method: "POST" });
  console.log("Test webhook fired — check your local server logs");
}

Project Structure

instantly-integration/
├── src/
│   ├── config.ts           # Environment-aware config
│   ├── instantly.ts         # API client with retry
│   └── webhook-server.ts   # Local webhook receiver
├── tests/
│   └── instantly.test.ts   # Integration tests
├── .env.development         # Dev config (mock mode)
├── .env.production          # Prod config
├── package.json
└── tsconfig.json

Error Handling

Error	Cause	Solution
Mock returns unexpected data	Mock schema mismatch	Check mock docs at developer.instantly.ai
ECONNREFUSED on localhost	Webhook server not running	Start it before registering webhook
Tests passing locally, failing in CI	Different env vars	Ensure CI uses .env.development
ngrok tunnel expired	Free tier 2-hour limit	Restart ngrok or upgrade

Resources

• Instantly Mock Server
• Instantly API v2 Docs
• ngrok Quick Start

Next Steps

For production SDK patterns, see instantly-sdk-patterns.