Server-side · v1

Transactional SMS API

Order confirmations, shipping updates, appointment reminders — the messages your product sends because something happened, not because you are running a campaign. One endpoint, DLT-approved templates, and an idempotency key so a retry after a timeout cannot send twice.

Let your coding assistant do this

Claude Code, Cursor, Copilot and Windsurf can wire this up for you. The prompt below points them at our integration guide, which carries every endpoint with its real field names, status codes and response shapes rather than a summary they have to guess at.

prompt

Read https://quickauth.in/llms-full.txt — it is QuickAuth's integration guide, with the real endpoint paths, field names and response shapes. Then add transactional SMS through QuickAuth to this project, following the conventions already in the codebase. Keep the client id and secret in environment variables and never in client-side code.

Open in Claude Open in ChatGPT Read the guide

This is not the OTP endpoint

Login codes go through the authentication API. Keeping them apart is deliberate: OTP delivery rate is a number you watch closely, and folding order updates into it moves that number for reasons that have nothing to do with whether people can log in. They are also billed separately.

Send a message

POST/v1/sms/send

Send one transactional SMS

Sends immediately and returns what happened. The template must already be DLT-approved on your account.

curl https://api.quickauth.in/v1/sms/send \
  -H "Content-Type: application/json" \
  -H "X-Client-Id: $CLIENT_ID" \
  -H "X-Client-Secret: $CLIENT_SECRET" \
  -d '{
    "templateId": "order_shipped",
    "to": "919876543210",
    "variables": ["Rohit", "ORD-42"],
    "idempotencyKey": "order-42-shipped"
  }'

Request fields

Field	Required	What it does
`templateId`	Yes	A DLT-approved template on your account.
`to`	Yes	Recipient in international format — `919876543210`, no leading `+`.
`variables`	—	Values for the template’s placeholders, in order. Position is load-bearing.
`variableValues`	—	The same values keyed by name, if you would rather not depend on order.
`senderId`	—	Overrides your account’s default sender ID.
`idempotencyKey`	—	The same key never sends twice. See below — you want this.

Use an idempotency key

A network timeout tells you nothing about whether the message was sent. Without a key, the safe-looking retry is how a customer gets the same alert twice; with one, the retry is free. Derive it from something stable in your domain — order-42-shipped, not a random UUID generated at call time, which changes on the retry and defeats the point.

Response

{
  "messageId": "SP-8f2a91c3",
  "status":    "SENT",
  "to":        "919876543210"
}

status is SENT when the carrier accepted the message. It is not a delivery confirmation — see below.

Responses

200The carrier accepted it. A repeat of a known idempotencyKey returns the original result rather than sending again.
400A field is missing or malformed.INVALID_REQUEST
400No such template on your account, or it is not approved.TEMPLATE_NOT_FOUND
401Client id or secret is wrong.INVALID_CLIENT_CREDENTIALS
402Out of SMS credit.INSUFFICIENT_SMS_BALANCE
429Rate limited.RATE_LIMIT_EXCEEDED
502The SMS provider refused the send.PROVIDER_ERROR

DLT, briefly

Indian regulation requires every transactional SMS template to be registered with DLT before it can be delivered. This is a TRAI requirement carried by every operator, not a QuickAuth rule — an unregistered template is rejected by the carrier, not by us. Register templates from the dashboard; approval usually takes a few hours.

Delivery is reported, not returned

A 200 means the carrier accepted the message. Whether it reached the handset arrives later — subscribe to delivery.delivered and delivery.failed under Webhooks in the dashboard, or read the SMS analytics page.