API Tutorial
How to post to WhatsApp via API
To post to WhatsApp via API, connect the WhatsApp account through Modiva (which handles OAuth and scopes), then call the `posts_create` tool with your text and media — Modiva publishes it to WhatsApp and returns the post ID.
WhatsApp's own API requires app review, OAuth handling and the right publishing permissions before you can post a single update. Modiva does all of that for you and exposes a single `posts_create` tool that publishes to WhatsApp (and every other connected platform) the same way.
Step by step
Create a Modiva account and MCP key
Sign up free and generate an MCP key (`mk_live_…`) from the dashboard. The same key authenticates both the hosted MCP server (for AI agents) and the REST API (for your backend), so you only manage one credential.
Connect your WhatsApp account
From the dashboard, click Connect and choose WhatsApp. Modiva runs the OAuth flow and requests the right scopes for you, then stores the access + refresh tokens in an encrypted vault and keeps them fresh — you never handle WhatsApp's raw API credentials. The connection gets a stable `connectionId` you reference in every call.
Call posts_create to publish to WhatsApp
Invoke the `posts_create` tool with the connection ID and your content. Modiva validates the payload against WhatsApp's format rules (length, media types, aspect ratios) and publishes immediately, returning the live post ID and URL.
Go further — schedule, cross-post, automate
The same call powers an AI agent over MCP: point Claude or Cursor at `https://mcp.modiva.ai/v1` and it can post to WhatsApp on your behalf. Swap `posts_create` for `posts_schedule` to queue it, or `posts_cross_post` to fan one post out to every platform at once.
Example request
Call the posts_create tool through Modiva’s REST API. The same tool is available to AI agents over the MCP server at https://mcp.modiva.ai/v1.
curl -X POST https://api.modiva.ai/v1/tools/invoke \
-H "Authorization: Bearer mk_live_…" \
-H "Content-Type: application/json" \
-d '{
"tool": "posts_create",
"connectionId": "conn_…",
"args": { "text": "Shipped via Modiva 🚀" }
}'Try it with WhatsApp
Start freeFAQ
Do I need a WhatsApp developer app to post via the API?
No. Modiva owns the reviewed WhatsApp app and handles OAuth, so you connect with a click and start posting — no app review, no scope wrangling.
Can an AI agent post to WhatsApp for me?
Yes. The same `posts_create` tool is exposed over the Model Context Protocol, so any MCP client (Claude, Cursor, etc.) can publish to WhatsApp once you add your Modiva MCP key.