What is the easiest way to implement the WhatsApp Business API?

Use Messlo’s REST API: connect your WABA once in the dashboard, generate an API key, and call documented endpoints with standard HTTP tools (cURL, Postman, or any SDK). You avoid direct Meta app review complexity for common messaging, contacts, templates, and campaigns.

How do I send a WhatsApp message via API?

Authenticate with X-API-Key, obtain your phone_number_id from GET /api/whatsapp/phone-numbers, then POST to /api/whatsapp/send (session messages) or use template endpoints for marketing and notifications.

Is this the official WhatsApp Business API?

Yes. Messlo integrates with the WhatsApp Business Platform (Cloud API). Your messages are sent through your connected WABA and comply with Meta’s messaging policies and template rules.

How does API authentication work?

Include your API key in the X-API-Key header or as Authorization: ApiKey . JWT Bearer tokens are used for dashboard sessions; server-to-server integrations should use API keys.

Can I send bulk WhatsApp messages or campaigns via API?

Yes. Use the Broadcast API to create campaigns, attach an approved template, and send to contact lists or segments. List campaigns with GET /api/campaigns before creating new sends.

How does Login with WhatsApp work?

Create a Login app in the Messlo dashboard (choose your WhatsApp Business number or Messlo's shared number). Use @getmesslo/messlo-node-sdk and @getmesslo/messlo-whatsapp-login for production integrations, or call POST /v1/auth/whatsapp/start with your app API key to get a waLink. The user sends the pre-filled LOGIN message on WhatsApp. Listen via SSE on GET /v1/auth/whatsapp/events/:sessionId or poll GET /status until you receive verificationToken, then POST /v1/auth/verify-token on your backend. Full guide: /developers/login-with-whatsapp. Example repo: github.com/GetMesslo/nextjs-whatsapp-login-demo.

Are there official SDKs for Login with WhatsApp?

Yes. @getmesslo/messlo-node-sdk provides backend helpers and Next.js/Express route adapters. @getmesslo/messlo-whatsapp-login provides a React hook and UI components for your frontend (via your proxy routes). See npmjs.com/package/@getmesslo/messlo-node-sdk and npmjs.com/package/@getmesslo/messlo-whatsapp-login.

Where can LLMs and tools find a summary of this API?

A machine-readable summary is available at /llms.txt on this site, alongside this HTML documentation page. Install @getmesslo/messlo-mcp in Cursor for natural-language setup (messlo_plan_integration goals: inbound_automation, ecommerce_checkout, industry_pack_onboarding, and more).

How do I build WhatsApp automation flows via API?

POST /api/automation with nodes, connections, and triggers (typically message_received). GET /api/automation/node-types for the full node catalog. Use PATCH /api/automation/:flowId/toggle to activate. Cursor users can use messlo_compose_automation_flow or apply an industry pack via POST /api/industry-packs/apply.

How do I send order confirmations with a dynamic PDF header?

Create a template with a public header_url sample (document type) via POST /api/template/create, wait for Meta approval, then POST /api/whatsapp/send with messageType template and mediaUrl set to the per-order PDF URL. Alternatively, use POST /api/ecommerce-webhook/create and map-template for Shopify or WooCommerce order webhooks.

Messlo · WhatsApp Business API

WhatsApp Business API documentation — easiest REST integration

Messlo provides a developer-friendly REST API on top of the official WhatsApp Business Platform (Cloud API). Integrate WhatsApp messaging into your product, CRM, or automation stack without building Meta infrastructure from scratch.

Use this page as your complete WhatsApp API reference: authentication, endpoint list, request examples, and copy-ready cURL commands. Sign up free to generate an API key and test endpoints from the browser.

Quick start — implement WhatsApp API in minutes

Create a Messlo account and connect WhatsAppRegister at Messlo, connect your WhatsApp Business Account (WABA), and verify your phone number in the dashboard.
Generate an API keyOpen Integration Tools → API Credentials and create a key. Store it securely — it is shown only once.
Optional: Messlo MCP in CursorInstall @getmesslo/messlo-mcp in Cursor MCP settings (see Integration Tools → Cursor MCP). Ask the AI to create templates, API keys, or check integration status.
Call the REST API with your keySend the X-API-Key header (or Authorization: ApiKey <key>) on every request. Start with GET /api/whatsapp/connections to list your WABA IDs.
Send your first messagePOST to /api/whatsapp/send with phone_number_id, recipient, and message payload. Use approved templates for outbound marketing outside the 24-hour window.
Optional: Login with WhatsAppCreate a Login app in Messlo. Use npm packages @getmesslo/messlo-node-sdk (backend) and @getmesslo/messlo-whatsapp-login (React/Next.js), or call REST directly. See /developers#whatsapp-auth and the demo at github.com/GetMesslo/nextjs-whatsapp-login-demo.

Example: list WhatsApp connections

curl -s -X GET "https://api.messlo.com/api/whatsapp/connections" \
  -H "X-API-Key: YOUR_API_KEY"

Example: send a text message

curl -s -X POST "https://api.messlo.com/api/whatsapp/send" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"contact_no":"919876543210","whatsapp_phone_number":"911234567890","messageType":"text","message":"Hello!"}'

Create a free account to get an API key and test requests in the browser.

Cursor MCP — build with AI in your IDE

Install @getmesslo/messlo-mcp in Cursor (or any MCP-compatible editor) to create API keys, templates, automation flows, checkout webhooks, and Login apps using natural language. Use messlo_plan_integration with goals like inbound_automation, ecommerce_checkout, or industry_pack_onboarding. After sign-in, open Integration Tools → Cursor MCP for config and example prompts.

{
  "mcpServers": {
    "messlo": {
      "command": "npx",
      "args": ["-y", "@getmesslo/messlo-mcp"],
      "env": {
        "MESSLO_API_KEY": "your_api_key_here"
      }
    }
  }
}

Login with WhatsApp — official SDKs & demo

Prefer npm packages over raw REST. Use @getmesslo/messlo-node-sdk on your backend and @getmesslo/messlo-whatsapp-login in React or Next.js. Clone the Next.js demo for a working full-stack reference.

Ship Login with WhatsApp faster using our published SDKs. Your API key and webhook secret stay on the server; the client SDK calls your proxy routes only.

Backend@getmesslo/messlo-node-sdkNode.js SDK for your backend: start sessions, poll status, verify tokens, proxy SSE, and verify webhook HMAC — API key stays server-side.npm React / Next.js@getmesslo/messlo-whatsapp-loginReact / Next.js client SDK: typed client, useMessloWhatsAppLogin hook, and a reference Login button — talks to your backend proxy routes, not Messlo directly.npm ExampleNext.js full-stack demoClone-ready example with App Router API routes (start, status, SSE events), webhook handler, and a working Login with WhatsApp UI.GitHub

npm install @getmesslo/messlo-node-sdk npm install @getmesslo/messlo-whatsapp-login Open demo repo

Backend (.env)

MESSLO_WA_LOGIN_API_KEY=your_api_key_from_messlo_dashboard
MESSLO_WA_LOGIN_WEBHOOK_SECRET=your_webhook_secret_from_app_create
MESSLO_API_BASE_URL=https://api.messlo.com

Next.js proxy routes (Node SDK)

import { MessloNodeSdk, nextAdapter } from "@getmesslo/messlo-node-sdk";

const sdk = new MessloNodeSdk({
  apiKey: process.env.MESSLO_WA_LOGIN_API_KEY!,
  baseUrl: process.env.MESSLO_API_BASE_URL,
});

// app/api/auth/whatsapp-login/start/route.ts
export const POST = nextAdapter.startRoute(sdk);

// app/api/auth/whatsapp-login/status/[sessionId]/route.ts
export const GET = nextAdapter.statusRoute(sdk);

// app/api/auth/whatsapp-login/events/[sessionId]/route.ts
export const GET = nextAdapter.eventsRoute(sdk);

React hook (client SDK)

import { useMessloWhatsAppLogin } from "@getmesslo/messlo-whatsapp-login/react";

const { startLogin, status, waLink, error } = useMessloWhatsAppLogin({
  basePath: "/api/auth/whatsapp-login",
  onVerified: async (verificationToken) => {
    await fetch("/api/auth/session", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ verificationToken }),
    });
  },
});

Complete WhatsApp REST API endpoint reference

All endpoints use HTTPS and API key authentication. Base URL: https://api.messlo.com

WhatsApp Configuration

Handle WhatsApp account connections and numbers. Call these endpoints first to obtain waba_id and phone numbers.

Method	Endpoint	Description
GET	/api/whatsapp/connections	Fetch WABA Connections
GET	/api/whatsapp/phone-numbers	Fetch All Phone Numbers
GET	/api/whatsapp/:wabaId/phone-numbers	Fetch WABA-Specific Phone NumbersReplace :wabaId with your WABA document ID or Meta business account ID.
POST	/api/whatsapp/:wabaId/webhooks/setup	Setup WABA webhooks (Meta)Subscribe Meta webhooks for inbound messages and delivery events. Business API (Cloud API) only — run after connecting WABA.
POST	/api/whatsapp/workspace/sync	Sync workspace from Meta

Login with WhatsApp

Verify users via WhatsApp without OTP: create a Login app in Messlo, then integrate with @getmesslo/messlo-node-sdk and @getmesslo/messlo-whatsapp-login (recommended) or call the REST endpoints below. Example app: github.com/GetMesslo/nextjs-whatsapp-login-demo. Each Login app stores whether users message your WABA or Messlo's shared number; Messlo returns a verification JWT — validate it on your server and issue your own session.

Method	Endpoint	Description
POST	/v1/auth/whatsapp/start	Start auth sessionCreates a pending session and returns a wa.me deep link. The user must send the pre-filled LOGIN message from their WhatsApp app. Optional phone_number_id selects which connected number receives the login message (defaults to primary active Cloud API phone). Set use_messlo_phone to true to use Messlo's shared number instead — mutually exclusive with phone_number_id.
GET	/v1/auth/whatsapp/events/:sessionId?token={subscribeToken}	Listen for verification (SSE)Open a Server-Sent Events stream using subscribeToken from /start. Messlo pushes verified when Meta webhook receives the user's LOGIN message — preferred over polling at scale.
GET	/v1/auth/whatsapp/status/:sessionId	Get verification token (optional poll)One-shot or fallback poll after SSE verified (or if you cannot use SSE). Returns verificationToken when the session is success.
POST	/v1/auth/verify-token	Verify token (server-side)Your backend validates the Messlo-signed JWT and receives the verified phone and profile name. Token is single-use. Issue your own app JWT/session after this call.

Contact Management System

Organize contacts and their associations.

Method	Endpoint	Description
GET	/api/contacts	List Contacts
POST	/api/contacts	Create Contact

Interactive Messaging API

Deliver engaging messages to your contacts

Method	Endpoint	Description
POST	/api/whatsapp/send	Send Text MessageNote: `contact_no` is the receiver's phone number, and `whatsapp_phone_number` is the sender's registered phone number. Ensure that a WABA is connected with this sender number for the request to work.
POST	/api/whatsapp/send	Upload Image (URL)
POST	/api/whatsapp/send	Upload Document (URL)
POST	/api/whatsapp/send	Send Video via URL
POST	/api/whatsapp/send	Share Location Info
POST	/api/whatsapp/send	Send Multiple Media via URLsSends multiple media files in sequence using public URLs.
POST	/api/whatsapp/send	Send approved templateSend a Meta-approved template. Use mediaUrl for a dynamic document/image header per message (e.g. invoice PDF URL at checkout).
POST	/api/whatsapp/send	Send Media from Local Device
GET	/api/whatsapp/chats	List recent chatsInbox threads for debugging automations.
GET	/api/whatsapp/messages	List messages in threadQuery: contact_id (from chats or contacts).
POST	/api/whatsapp/assign-chat	Assign chat to agent
POST	/api/whatsapp/send	Send Audio via URL

Messaging Templates API

Manage and send predefined WhatsApp message templates.

Method	Endpoint	Description
POST	/api/template/create	Simple TemplateStart here — basic MARKETING template with body and optional footer.
POST	/api/template/create	Template with Variables
POST	/api/template/create	Template with Quick Reply Buttons
POST	/api/template/create	Template with CTA Buttons
POST	/api/template/create	Template with Coupon Code
POST	/api/template/create	OTP / Authentication Templatecategory must be AUTHENTICATION — enables OTP-specific fields and buttons.
POST	/api/template/create	Limited Time Offer Template
POST	/api/template/create	Template with Catalog Button
POST	/api/template/create	Template with Call Permission
POST	/api/template/create	Carousel Template
POST	/api/template/create	Template with document header (URL)Use a public HTTPS URL for the sample PDF/image/video header. Meta requires the URL to be reachable at create time.
POST	/api/template/validate-media-url	Validate template media URL
POST	/api/template/sync-status	Sync template approval status

Broadcast API

Launch and control bulk messaging campaigns.

Method	Endpoint	Description
GET	/api/campaigns	Campaign ListList existing campaigns and statuses before creating a new send.
POST	/api/campaigns	Setup Campaign (All Contacts)Simplest broadcast — sends an approved template to every contact.
POST	/api/campaigns	Setup Campaign (Specific Contacts)
POST	/api/campaigns	Setup Scheduled Campaign (By Tags)
POST	/api/campaigns	Setup Campaign with Media
POST	/api/campaigns	Setup Campaign with Dynamic Coupon
POST	/api/campaigns	Setup Campaign for Limited Time Offer
POST	/api/campaigns	Setup Campaign with Product Carousel
POST	/api/campaigns	Setup Campaign with Media Carousel
POST	/api/campaigns	Setup Campaign with Media Carousel (Local Files)

Automation flows

WhatsApp bot flows as JSON (nodes, connections, triggers). Build in the dashboard or use @getmesslo/messlo-mcp (messlo_compose_automation_flow, industry packs).

Method	Endpoint	Description
GET	/api/automation	List automation flows
GET	/api/automation/node-types	Node types catalogAll valid node types and parameters for flow JSON.
POST	/api/automation	Create automation flow
PATCH	/api/automation/:flowId/toggle	Toggle flow active
POST	/api/automation/:flowId/test	Test flow
GET	/api/automation/:flowId/executions	List executions

CRM: segments, tags & custom fields

Organize contacts for automations (add_to_segment, add_tag, update_contact nodes) and broadcast campaigns.

Method	Endpoint	Description
GET	/api/segments	List segments
POST	/api/segments	Create segment
GET	/api/tags	List tags
POST	/api/tags	Create tag
GET	/api/custom-fields	List custom fields
PUT	/api/contacts/:id	Update contact

AI chatbots & keyword bots

AI assistants (assign_chatbot nodes) and keyword auto-replies (message bots). Quick replies are agent inbox shortcuts.

Method	Endpoint	Description
GET	/api/chatbots	List chatbotsQuery: waba_id (required).
POST	/api/chatbots	Create chatbot
POST	/api/chatbots/:id/train	Train chatbot (Q&A)
GET	/api/message-bots	List message botsQuery: waba_id (required).
POST	/api/message-bots	Create message bot
GET	/api/quick-replies	List quick replies

WhatsApp Flow forms

Meta Flow lead forms. In automations, form_flow nodes use flow.flow_id from GET form (not the MongoDB form _id).

Method	Endpoint	Description
GET	/api/forms	List formsQuery: waba_id (required).
POST	/api/forms	Create form
PATCH	/api/forms/:id/publish	Publish form

Industry packs

One-shot vertical onboarding: CRM fields, tags, segments, automation flows, and chatbot presets per industry.

Method	Endpoint	Description
GET	/api/industry-packs/public	List public packs
GET	/api/industry-packs/public/:slug/preview	Preview packOptional query: company_name, city, etc.
POST	/api/industry-packs/apply	Apply pack

Ops & integrations

Agents, drip sequences, Google Sheets/Calendar, plan usage, kanban pipelines, and bulk imports.

Method	Endpoint	Description
GET	/api/subscriptions/usage	Subscription usage
GET	/api/agent/all	List agents
POST	/api/whatsapp/assign-chat	Assign chat to agent
GET	/api/google/connect	Google OAuth connectReturns URL to connect Google account.
GET	/api/sequences	List sequencesQuery: waba_id (required).
GET	/api/kanban-funnels	List kanban funnels

Commerce & checkout

Meta catalogs, order webhooks (Shopify/WooCommerce), and template sends with dynamic header media (e.g. per-order PDF via mediaUrl).

Method	Endpoint	Description
POST	/api/ecommerce-catalog/waba/:waba_id/sync-catalogs	Sync WABA catalogs
GET	/api/ecommerce-catalog/catalog/:catalog_id/products	List catalog products
POST	/api/ecommerce-webhook/create	Create order webhook
POST	/api/ecommerce-webhook/:id/map-template	Map template to webhook
POST	/api/whatsapp/send	Send template with dynamic PDF header

81 documented endpoints across messaging, contacts, templates, and campaigns.

Frequently asked questions — WhatsApp API integration

What is the easiest way to implement the WhatsApp Business API?: Use Messlo’s REST API: connect your WABA once in the dashboard, generate an API key, and call documented endpoints with standard HTTP tools (cURL, Postman, or any SDK). You avoid direct Meta app review complexity for common messaging, contacts, templates, and campaigns.
How do I send a WhatsApp message via API?: Authenticate with X-API-Key, obtain your phone_number_id from GET /api/whatsapp/phone-numbers, then POST to /api/whatsapp/send (session messages) or use template endpoints for marketing and notifications.
Is this the official WhatsApp Business API?: Yes. Messlo integrates with the WhatsApp Business Platform (Cloud API). Your messages are sent through your connected WABA and comply with Meta’s messaging policies and template rules.
How does API authentication work?: Include your API key in the X-API-Key header or as Authorization: ApiKey <your_key>. JWT Bearer tokens are used for dashboard sessions; server-to-server integrations should use API keys.
Can I send bulk WhatsApp messages or campaigns via API?: Yes. Use the Broadcast API to create campaigns, attach an approved template, and send to contact lists or segments. List campaigns with GET /api/campaigns before creating new sends.
How does Login with WhatsApp work?: Create a Login app in the Messlo dashboard (choose your WhatsApp Business number or Messlo's shared number). Use @getmesslo/messlo-node-sdk and @getmesslo/messlo-whatsapp-login for production integrations, or call POST /v1/auth/whatsapp/start with your app API key to get a waLink. The user sends the pre-filled LOGIN message on WhatsApp. Listen via SSE on GET /v1/auth/whatsapp/events/:sessionId or poll GET /status until you receive verificationToken, then POST /v1/auth/verify-token on your backend. Full guide: /developers/login-with-whatsapp. Example repo: github.com/GetMesslo/nextjs-whatsapp-login-demo.
Are there official SDKs for Login with WhatsApp?: Yes. @getmesslo/messlo-node-sdk provides backend helpers and Next.js/Express route adapters. @getmesslo/messlo-whatsapp-login provides a React hook and UI components for your frontend (via your proxy routes). See npmjs.com/package/@getmesslo/messlo-node-sdk and npmjs.com/package/@getmesslo/messlo-whatsapp-login.
Where can LLMs and tools find a summary of this API?: A machine-readable summary is available at /llms.txt on this site, alongside this HTML documentation page. Install @getmesslo/messlo-mcp in Cursor for natural-language setup (messlo_plan_integration goals: inbound_automation, ecommerce_checkout, industry_pack_onboarding, and more).
How do I build WhatsApp automation flows via API?: POST /api/automation with nodes, connections, and triggers (typically message_received). GET /api/automation/node-types for the full node catalog. Use PATCH /api/automation/:flowId/toggle to activate. Cursor users can use messlo_compose_automation_flow or apply an industry pack via POST /api/industry-packs/apply.
How do I send order confirmations with a dynamic PDF header?: Create a template with a public header_url sample (document type) via POST /api/template/create, wait for Meta approval, then POST /api/whatsapp/send with messageType template and mediaUrl set to the per-order PDF URL. Alternatively, use POST /api/ecommerce-webhook/create and map-template for Shopify or WooCommerce order webhooks.

Messlo · WhatsApp Business API

WhatsApp Business API documentation — easiest REST integration

Quick start — implement WhatsApp API in minutes

Create a Messlo account and connect WhatsAppRegister at Messlo, connect your WhatsApp Business Account (WABA), and verify your phone number in the dashboard.
Generate an API keyOpen Integration Tools → API Credentials and create a key. Store it securely — it is shown only once.
Optional: Messlo MCP in CursorInstall @getmesslo/messlo-mcp in Cursor MCP settings (see Integration Tools → Cursor MCP). Ask the AI to create templates, API keys, or check integration status.
Call the REST API with your keySend the X-API-Key header (or Authorization: ApiKey <key>) on every request. Start with GET /api/whatsapp/connections to list your WABA IDs.
Send your first messagePOST to /api/whatsapp/send with phone_number_id, recipient, and message payload. Use approved templates for outbound marketing outside the 24-hour window.
Optional: Login with WhatsAppCreate a Login app in Messlo. Use npm packages @getmesslo/messlo-node-sdk (backend) and @getmesslo/messlo-whatsapp-login (React/Next.js), or call REST directly. See /developers#whatsapp-auth and the demo at github.com/GetMesslo/nextjs-whatsapp-login-demo.

Example: list WhatsApp connections

curl -s -X GET "https://api.messlo.com/api/whatsapp/connections" \
  -H "X-API-Key: YOUR_API_KEY"

Example: send a text message

curl -s -X POST "https://api.messlo.com/api/whatsapp/send" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"contact_no":"919876543210","whatsapp_phone_number":"911234567890","messageType":"text","message":"Hello!"}'

Create a free account to get an API key and test requests in the browser.

Cursor MCP — build with AI in your IDE

{
  "mcpServers": {
    "messlo": {
      "command": "npx",
      "args": ["-y", "@getmesslo/messlo-mcp"],
      "env": {
        "MESSLO_API_KEY": "your_api_key_here"
      }
    }
  }
}

Login with WhatsApp — official SDKs & demo

Prefer npm packages over raw REST. Use @getmesslo/messlo-node-sdk on your backend and @getmesslo/messlo-whatsapp-login in React or Next.js. Clone the Next.js demo for a working full-stack reference.

Ship Login with WhatsApp faster using our published SDKs. Your API key and webhook secret stay on the server; the client SDK calls your proxy routes only.

npm install @getmesslo/messlo-node-sdk npm install @getmesslo/messlo-whatsapp-login Open demo repo

Backend (.env)

MESSLO_WA_LOGIN_API_KEY=your_api_key_from_messlo_dashboard
MESSLO_WA_LOGIN_WEBHOOK_SECRET=your_webhook_secret_from_app_create
MESSLO_API_BASE_URL=https://api.messlo.com

Next.js proxy routes (Node SDK)

import { MessloNodeSdk, nextAdapter } from "@getmesslo/messlo-node-sdk";

const sdk = new MessloNodeSdk({
  apiKey: process.env.MESSLO_WA_LOGIN_API_KEY!,
  baseUrl: process.env.MESSLO_API_BASE_URL,
});

// app/api/auth/whatsapp-login/start/route.ts
export const POST = nextAdapter.startRoute(sdk);

// app/api/auth/whatsapp-login/status/[sessionId]/route.ts
export const GET = nextAdapter.statusRoute(sdk);

// app/api/auth/whatsapp-login/events/[sessionId]/route.ts
export const GET = nextAdapter.eventsRoute(sdk);

React hook (client SDK)

import { useMessloWhatsAppLogin } from "@getmesslo/messlo-whatsapp-login/react";

const { startLogin, status, waLink, error } = useMessloWhatsAppLogin({
  basePath: "/api/auth/whatsapp-login",
  onVerified: async (verificationToken) => {
    await fetch("/api/auth/session", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ verificationToken }),
    });
  },
});

Complete WhatsApp REST API endpoint reference

All endpoints use HTTPS and API key authentication. Base URL: https://api.messlo.com

WhatsApp Configuration

Handle WhatsApp account connections and numbers. Call these endpoints first to obtain waba_id and phone numbers.

Method	Endpoint	Description
GET	/api/whatsapp/connections	Fetch WABA Connections
GET	/api/whatsapp/phone-numbers	Fetch All Phone Numbers
GET	/api/whatsapp/:wabaId/phone-numbers	Fetch WABA-Specific Phone NumbersReplace :wabaId with your WABA document ID or Meta business account ID.
POST	/api/whatsapp/:wabaId/webhooks/setup	Setup WABA webhooks (Meta)Subscribe Meta webhooks for inbound messages and delivery events. Business API (Cloud API) only — run after connecting WABA.
POST	/api/whatsapp/workspace/sync	Sync workspace from Meta

Login with WhatsApp

Method	Endpoint	Description
POST	/v1/auth/whatsapp/start	Start auth sessionCreates a pending session and returns a wa.me deep link. The user must send the pre-filled LOGIN message from their WhatsApp app. Optional phone_number_id selects which connected number receives the login message (defaults to primary active Cloud API phone). Set use_messlo_phone to true to use Messlo's shared number instead — mutually exclusive with phone_number_id.
GET	/v1/auth/whatsapp/events/:sessionId?token={subscribeToken}	Listen for verification (SSE)Open a Server-Sent Events stream using subscribeToken from /start. Messlo pushes verified when Meta webhook receives the user's LOGIN message — preferred over polling at scale.
GET	/v1/auth/whatsapp/status/:sessionId	Get verification token (optional poll)One-shot or fallback poll after SSE verified (or if you cannot use SSE). Returns verificationToken when the session is success.
POST	/v1/auth/verify-token	Verify token (server-side)Your backend validates the Messlo-signed JWT and receives the verified phone and profile name. Token is single-use. Issue your own app JWT/session after this call.

Contact Management System

Organize contacts and their associations.

Method	Endpoint	Description
GET	/api/contacts	List Contacts
POST	/api/contacts	Create Contact

Interactive Messaging API

Deliver engaging messages to your contacts

Method	Endpoint	Description
POST	/api/whatsapp/send	Send Text MessageNote: `contact_no` is the receiver's phone number, and `whatsapp_phone_number` is the sender's registered phone number. Ensure that a WABA is connected with this sender number for the request to work.
POST	/api/whatsapp/send	Upload Image (URL)
POST	/api/whatsapp/send	Upload Document (URL)
POST	/api/whatsapp/send	Send Video via URL
POST	/api/whatsapp/send	Share Location Info
POST	/api/whatsapp/send	Send Multiple Media via URLsSends multiple media files in sequence using public URLs.
POST	/api/whatsapp/send	Send approved templateSend a Meta-approved template. Use mediaUrl for a dynamic document/image header per message (e.g. invoice PDF URL at checkout).
POST	/api/whatsapp/send	Send Media from Local Device
GET	/api/whatsapp/chats	List recent chatsInbox threads for debugging automations.
GET	/api/whatsapp/messages	List messages in threadQuery: contact_id (from chats or contacts).
POST	/api/whatsapp/assign-chat	Assign chat to agent
POST	/api/whatsapp/send	Send Audio via URL

Messaging Templates API

Manage and send predefined WhatsApp message templates.

Method	Endpoint	Description
POST	/api/template/create	Simple TemplateStart here — basic MARKETING template with body and optional footer.
POST	/api/template/create	Template with Variables
POST	/api/template/create	Template with Quick Reply Buttons
POST	/api/template/create	Template with CTA Buttons
POST	/api/template/create	Template with Coupon Code
POST	/api/template/create	OTP / Authentication Templatecategory must be AUTHENTICATION — enables OTP-specific fields and buttons.
POST	/api/template/create	Limited Time Offer Template
POST	/api/template/create	Template with Catalog Button
POST	/api/template/create	Template with Call Permission
POST	/api/template/create	Carousel Template
POST	/api/template/create	Template with document header (URL)Use a public HTTPS URL for the sample PDF/image/video header. Meta requires the URL to be reachable at create time.
POST	/api/template/validate-media-url	Validate template media URL
POST	/api/template/sync-status	Sync template approval status

Broadcast API

Launch and control bulk messaging campaigns.

Method	Endpoint	Description
GET	/api/campaigns	Campaign ListList existing campaigns and statuses before creating a new send.
POST	/api/campaigns	Setup Campaign (All Contacts)Simplest broadcast — sends an approved template to every contact.
POST	/api/campaigns	Setup Campaign (Specific Contacts)
POST	/api/campaigns	Setup Scheduled Campaign (By Tags)
POST	/api/campaigns	Setup Campaign with Media
POST	/api/campaigns	Setup Campaign with Dynamic Coupon
POST	/api/campaigns	Setup Campaign for Limited Time Offer
POST	/api/campaigns	Setup Campaign with Product Carousel
POST	/api/campaigns	Setup Campaign with Media Carousel
POST	/api/campaigns	Setup Campaign with Media Carousel (Local Files)

Automation flows

WhatsApp bot flows as JSON (nodes, connections, triggers). Build in the dashboard or use @getmesslo/messlo-mcp (messlo_compose_automation_flow, industry packs).

Method	Endpoint	Description
GET	/api/automation	List automation flows
GET	/api/automation/node-types	Node types catalogAll valid node types and parameters for flow JSON.
POST	/api/automation	Create automation flow
PATCH	/api/automation/:flowId/toggle	Toggle flow active
POST	/api/automation/:flowId/test	Test flow
GET	/api/automation/:flowId/executions	List executions

CRM: segments, tags & custom fields

Organize contacts for automations (add_to_segment, add_tag, update_contact nodes) and broadcast campaigns.

Method	Endpoint	Description
GET	/api/segments	List segments
POST	/api/segments	Create segment
GET	/api/tags	List tags
POST	/api/tags	Create tag
GET	/api/custom-fields	List custom fields
PUT	/api/contacts/:id	Update contact

AI chatbots & keyword bots

AI assistants (assign_chatbot nodes) and keyword auto-replies (message bots). Quick replies are agent inbox shortcuts.

Method	Endpoint	Description
GET	/api/chatbots	List chatbotsQuery: waba_id (required).
POST	/api/chatbots	Create chatbot
POST	/api/chatbots/:id/train	Train chatbot (Q&A)
GET	/api/message-bots	List message botsQuery: waba_id (required).
POST	/api/message-bots	Create message bot
GET	/api/quick-replies	List quick replies

WhatsApp Flow forms

Meta Flow lead forms. In automations, form_flow nodes use flow.flow_id from GET form (not the MongoDB form _id).

Method	Endpoint	Description
GET	/api/forms	List formsQuery: waba_id (required).
POST	/api/forms	Create form
PATCH	/api/forms/:id/publish	Publish form

Industry packs

One-shot vertical onboarding: CRM fields, tags, segments, automation flows, and chatbot presets per industry.

Method	Endpoint	Description
GET	/api/industry-packs/public	List public packs
GET	/api/industry-packs/public/:slug/preview	Preview packOptional query: company_name, city, etc.
POST	/api/industry-packs/apply	Apply pack

Ops & integrations

Agents, drip sequences, Google Sheets/Calendar, plan usage, kanban pipelines, and bulk imports.

Method	Endpoint	Description
GET	/api/subscriptions/usage	Subscription usage
GET	/api/agent/all	List agents
POST	/api/whatsapp/assign-chat	Assign chat to agent
GET	/api/google/connect	Google OAuth connectReturns URL to connect Google account.
GET	/api/sequences	List sequencesQuery: waba_id (required).
GET	/api/kanban-funnels	List kanban funnels

Commerce & checkout

Meta catalogs, order webhooks (Shopify/WooCommerce), and template sends with dynamic header media (e.g. per-order PDF via mediaUrl).

Method	Endpoint	Description
POST	/api/ecommerce-catalog/waba/:waba_id/sync-catalogs	Sync WABA catalogs
GET	/api/ecommerce-catalog/catalog/:catalog_id/products	List catalog products
POST	/api/ecommerce-webhook/create	Create order webhook
POST	/api/ecommerce-webhook/:id/map-template	Map template to webhook
POST	/api/whatsapp/send	Send template with dynamic PDF header

81 documented endpoints across messaging, contacts, templates, and campaigns.

Frequently asked questions — WhatsApp API integration

What is the easiest way to implement the WhatsApp Business API?: Use Messlo’s REST API: connect your WABA once in the dashboard, generate an API key, and call documented endpoints with standard HTTP tools (cURL, Postman, or any SDK). You avoid direct Meta app review complexity for common messaging, contacts, templates, and campaigns.
How do I send a WhatsApp message via API?: Authenticate with X-API-Key, obtain your phone_number_id from GET /api/whatsapp/phone-numbers, then POST to /api/whatsapp/send (session messages) or use template endpoints for marketing and notifications.
Is this the official WhatsApp Business API?: Yes. Messlo integrates with the WhatsApp Business Platform (Cloud API). Your messages are sent through your connected WABA and comply with Meta’s messaging policies and template rules.
How does API authentication work?: Include your API key in the X-API-Key header or as Authorization: ApiKey <your_key>. JWT Bearer tokens are used for dashboard sessions; server-to-server integrations should use API keys.
Can I send bulk WhatsApp messages or campaigns via API?: Yes. Use the Broadcast API to create campaigns, attach an approved template, and send to contact lists or segments. List campaigns with GET /api/campaigns before creating new sends.
How does Login with WhatsApp work?: Create a Login app in the Messlo dashboard (choose your WhatsApp Business number or Messlo's shared number). Use @getmesslo/messlo-node-sdk and @getmesslo/messlo-whatsapp-login for production integrations, or call POST /v1/auth/whatsapp/start with your app API key to get a waLink. The user sends the pre-filled LOGIN message on WhatsApp. Listen via SSE on GET /v1/auth/whatsapp/events/:sessionId or poll GET /status until you receive verificationToken, then POST /v1/auth/verify-token on your backend. Full guide: /developers/login-with-whatsapp. Example repo: github.com/GetMesslo/nextjs-whatsapp-login-demo.
Are there official SDKs for Login with WhatsApp?: Yes. @getmesslo/messlo-node-sdk provides backend helpers and Next.js/Express route adapters. @getmesslo/messlo-whatsapp-login provides a React hook and UI components for your frontend (via your proxy routes). See npmjs.com/package/@getmesslo/messlo-node-sdk and npmjs.com/package/@getmesslo/messlo-whatsapp-login.
Where can LLMs and tools find a summary of this API?: A machine-readable summary is available at /llms.txt on this site, alongside this HTML documentation page. Install @getmesslo/messlo-mcp in Cursor for natural-language setup (messlo_plan_integration goals: inbound_automation, ecommerce_checkout, industry_pack_onboarding, and more).
How do I build WhatsApp automation flows via API?: POST /api/automation with nodes, connections, and triggers (typically message_received). GET /api/automation/node-types for the full node catalog. Use PATCH /api/automation/:flowId/toggle to activate. Cursor users can use messlo_compose_automation_flow or apply an industry pack via POST /api/industry-packs/apply.
How do I send order confirmations with a dynamic PDF header?: Create a template with a public header_url sample (document type) via POST /api/template/create, wait for Meta approval, then POST /api/whatsapp/send with messageType template and mediaUrl set to the per-order PDF URL. Alternatively, use POST /api/ecommerce-webhook/create and map-template for Shopify or WooCommerce order webhooks.

Quick start — implement WhatsApp API in minutes

Example: list WhatsApp connections

Example: send a text message

Cursor MCP — build with AI in your IDE

Login with WhatsApp — official SDKs & demo

Official npm packages & demo

Complete WhatsApp REST API endpoint reference

WhatsApp Configuration

Login with WhatsApp

Contact Management System

Interactive Messaging API

Messaging Templates API

Broadcast API

Automation flows

CRM: segments, tags & custom fields

AI chatbots & keyword bots

WhatsApp Flow forms

Industry packs

Ops & integrations

Commerce & checkout

Frequently asked questions — WhatsApp API integration

API & Integration Guide

Recommended first

Fetch WABA Connections

Fetch All Phone Numbers

Fetch WABA-Specific Phone Numbers

Setup WABA webhooks (Meta)

Sync workspace from Meta

Quick start — implement WhatsApp API in minutes

Example: list WhatsApp connections

Example: send a text message

Cursor MCP — build with AI in your IDE

Login with WhatsApp — official SDKs & demo

Official npm packages & demo

Complete WhatsApp REST API endpoint reference

WhatsApp Configuration

Login with WhatsApp

Contact Management System

Interactive Messaging API

Messaging Templates API

Broadcast API

Automation flows

CRM: segments, tags & custom fields

AI chatbots & keyword bots

WhatsApp Flow forms

Industry packs

Ops & integrations

Commerce & checkout

Frequently asked questions — WhatsApp API integration

API & Integration Guide

Recommended first

Fetch WABA Connections

Fetch All Phone Numbers

Fetch WABA-Specific Phone Numbers

Setup WABA webhooks (Meta)

Sync workspace from Meta