Twilio Messaging API

What it covers

Programmable messaging APIs for SMS, MMS, WhatsApp, media, and delivery callbacks. The profile stays deliberately concise: use the linked official reference for endpoint schemas and current commercial terms.

Integration notes

Authenticate exactly as the provider documents, keep credentials out of client bundles, and retain upstream request identifiers when available. Pagination, retries, caching, and webhook verification should be implemented per product rather than inferred from another API.

Key endpoints

Endpoint	Description
POST /2010-04-01/Accounts/{sid}/Messages.json	Send SMS/MMS
GET /2010-04-01/Accounts/{sid}/Messages.json	List messages
GET /2010-04-01/Accounts/{sid}/Messages/{sid}.json	Message details
POST /2010-04-01/Accounts/{sid}/Calls.json	Make a call
GET /2010-04-01/Accounts/{sid}/Calls.json	List calls
GET /2010-04-01/Accounts/{sid}.json	Account details

Decision notes

Best suited to transactional messaging and delivery-status workflows. Before production, verify regulatory registration may be required. validate twilio webhook signatures. Mutable limits, prices, and versions were checked on 2026-09-13 and should be rechecked at purchase or deployment time.

Python example: send an SMS (basic auth)

import httpx
from httpx import BasicAuth

ACCOUNT_SID = "your_account_sid"
AUTH_TOKEN = "your_auth_token"
FROM_NUMBER = "+15551234567"  # your Twilio number

def send_sms(to: str, body: str) -> dict:
    """Send an SMS. Twilio uses basic auth + form-encoded bodies."""
    resp = httpx.post(
        f"https://api.twilio.com/2010-04-01/Accounts/{ACCOUNT_SID}/Messages.json",
        auth=BasicAuth(ACCOUNT_SID, AUTH_TOKEN),
        data={"From": FROM_NUMBER, "To": to, "Body": body},
        timeout=30,
    )
    if resp.status_code == 401:
        raise RuntimeError("Invalid Account SID / Auth Token")
    resp.raise_for_status()
    msg = resp.json()
    if msg.get("status") in ("failed", "undelivered"):
        raise RuntimeError(f"SMS failed: {msg.get('error_message')}")
    return {"sid": msg["sid"], "status": msg["status"]}

print(send_sms("+15559876543", "Hello from the API!"))

Notes:

• Basic auth with Account SID as username, Auth Token as password
• Trial accounts can only message verified numbers and prepend a trial notice
• The 2010-04-01 path segment is the API version — still current
• Check message status/error_code after sending; 201 Created doesn’t mean delivered