X-API-Key · REST · Webhooks · Postman

Messaging APIsbuilt for high-load delivery

One unified API for SMS, messengers and flash calls. Sandbox access, documented endpoints, Postman collections and webhooks — designed for engineers shipping at scale.

Get startedBrowse docs
Base URL
client.massiva.com
Auth
X-API-Key
Formats
JSON · REST
Channels
9 live
Quickstart

From zero to your first message in three steps

No SDK to install. Any HTTP client will do. Use the curl snippet to verify your key, then swap in your stack.

  1. 01

    Request access

    Register on the developer portal — fill in company, work email, and your use case.

    Open registration →
  2. 02

    Get your X-API-Key

    A Massiva admin reviews your request and issues a scoped API key (OMNI, Broadcast, Recipients).

    Auth guide →
  3. 03

    Send your first message

    Call POST /api/v1/messages with the key in the X-API-Key header. Track delivery via webhooks or EDRs.

    OMNI reference →
curl -X POST https://client.massiva.com/api/v1/messages \
  -H "X-API-Key: $MASSIVA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contact": "905063565285",
    "channel": 1,
    "senderId": "MASSIVA",
    "payload": { "text": "Hello from Massiva" }
  }'

Returns messageId plus a delivery webhook to your registered URL. See delivery statuses and webhook reference.

API surfaces

Four endpoints. Everything you ship.

All documentation →
POST/api/v1/messages

OMNI

Single endpoint to send across SMS, WhatsApp, Viber, RCS, Telegram, Email, Push, TTS and WeChat.

Open reference →
POST/api/v1/broadcasts

Broadcast

Schedule mass campaigns, manage templates and target audiences with detailed delivery reports.

Open reference →
POST/api/v1/recipients

Recipients

Contact directory with attributes, tags, segments and reusable filter expressions.

Open reference →
POST/api/v1/payments

Payments

BackOffice payments, balance top-ups and invoicing with X-Private-Token authentication.

Open reference →
Channels

Nine channels through one API.

Use the same POST /messages endpoint — the channel integer selects transport.

Downloads

Postman, curl, ready to import.

All downloads →

OMNI Postman collection

Channels, senders, templates, EDRs, messages, omnimessages, Telegram Gateway verify/revoke.

Download

Broadcast / Recipients / Payments

Campaign management, contact directory, and BackOffice payments — single Postman collection.

Download

curl examples

Bash scripts for the most common flows: send SMS, WhatsApp template, RCS, fallback, OTP, EDRs.

Download

Open source on GitHub

Reference clients, webhook receivers, OpenAPI specs and Postman collections live in the open. Star, fork, or open a pull request.

View on GitHub

Start building today

Request developer access. Once approved you get a sandbox API key and full documentation for OMNI, Broadcast, Recipients and Payments.

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