API documentation

Authentication

Every request must include your API key as a Bearer token in the Authorization header. Keep your key secret and send it only over HTTPS.

Authorization: Bearer $A2P_API_KEY

Send a message

Send an SMS to one or more recipients. Provide the destination in E.164 format, a sender ID or number, and the message text. Long messages are automatically split into multiple segments.

Body parameters

Example request

curl -X POST https://api.a2ppro.com/v1/messages \
  -H "Authorization: Bearer $A2P_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+14155550123",
    "from": "A2P Pro",
    "text": "Your verification code is 7788"
  }'

const res = await fetch("https://api.a2ppro.com/v1/messages", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.A2P_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    to: "+14155550123",
    from: "A2P Pro",
    text: "Your verification code is 7788",
  }),
});

const message = await res.json();
console.log(message.id, message.status);

import os, requests

res = requests.post(
    "https://api.a2ppro.com/v1/messages",
    headers={"Authorization": f"Bearer {os.environ['A2P_API_KEY']}"},
    json={
        "to": "+14155550123",
        "from": "A2P Pro",
        "text": "Your verification code is 7788",
    },
)

message = res.json()
print(message["id"], message["status"])

Example response

{
  "id": "m-abc123",
  "status": "queued",
  "to": "+14155550123",
  "from": "A2P Pro",
  "segments": 1,
  "created_at": "2026-05-29T15:30:45Z"
}

The status field starts as queued, transitions to sent when handed to the carrier, and resolves to delivered or failed. The segments field reports how many SMS parts were used.

Message status

Retrieve the current status of a previously sent message by its id. Useful for polling when you have not configured a webhook.

curl https://api.a2ppro.com/v1/messages/m-abc123 \
  -H "Authorization: Bearer $A2P_API_KEY"

{
  "id": "m-abc123",
  "status": "delivered",
  "to": "+14155550123",
  "from": "A2P Pro",
  "segments": 1,
  "created_at": "2026-05-29T15:30:45Z",
  "delivered_at": "2026-05-29T15:30:52Z"
}

Delivery receipts & webhooks

Set a callback_url on a message — or configure a default endpoint on your account — and A2P Pro will POST a JSON event each time a message changes state. Respond with 2xx to acknowledge; non-2xx responses are retried with backoff.

Webhook events

Example payload

{
  "event": "message.delivered",
  "id": "m-abc123",
  "status": "delivered",
  "to": "+14155550123",
  "delivered_at": "2026-05-29T15:30:52Z"
}

Error codes

Errors return a non-2xx HTTP status and a JSON body with a machine-readable code and a human-readable message.

SMPP & CMPP connectivity

For high-throughput, low-latency traffic you can bind directly to our gateway over standard SMPP v3.4 or, for mainland China routes, CMPP v2.0/v3.0. Binds, throughput, and source addresses are provisioned per account.

Need host, port, and bind credentials? Contact sales and we will provision your SMPP/CMPP connection.

Rate limits & throughput

The platform sustains 1,000+ messages per second, and per-account throughput is provisioned to match your committed volume. If you exceed your allotted rate the API responds with 429 rate_limit_exceeded — back off and retry. SMPP/CMPP binds enforce throughput as a window size on the gateway.

Client libraries

Official SDKs wrap authentication and the REST endpoints so you can send a message in a few lines.