Welcome to Inbox's Developer Portal

Access powerful communication tools and integrate them seamlessly into your applications. Whether you're building a customer support system, a marketing automation tool, or a real-time communication solution, Inbox provides the APIs and resources you need to get started quickly and scale your business.

SMS API

Introduction

Inbox SMS API Endpoint

Inbox has an HTTP SMS service designed to let end-users send SMS messages using an HTTP interface. The API supports custom UDH, message scheduling, and other advanced features including Unicode formats.

Character Set Support

Supports GSM and Unicode (UTF-8 & Unicode-16 Big-Endian).

Message Length

Standard Latin: 160 characters
Unicode: 70 characters
Binary: 140 characters (including UDH)
Use UDH for long messages

Authorizations

Use a valid API Key
Only HTTPS is accepted
Responses in JSON
Errors return JSON with error keys

Rate Limit

Abide by rate limits to avoid blocks or restrictions.

Get Started

Base URL:

https://sms.Inbox.io/api.php?

Example GET Request:

https://sms.Inbox.io/api.php?username=abc&apikey=dOIni1jnnMFT&senderid=senderid&route=route_name&mobile=mobile_number&text=message

Curl Request:

Shell / cURL

curl -X POST \
'https://Inbox.in/api.php' \
-d 'username=your username' \
-d 'apikey=your api key' \
-d 'senderid=your sender id' \
-d 'route=Route which is assigned to you' \
-d 'mobile=xxxxxxxxxx' \
-d 'format=json' \
-d 'TID=Template ID' \
-d 'text=Message Text'

API Parameters

Parameter	Type	Description
username	Mandatory	Your account username.
apikey	Mandatory	Your API key from Inbox.
senderid	Mandatory	DLT-approved sender name (6 characters).
route	Mandatory	Assigned route (e.g., TRANS, PROMO, OTP).
mobile	Mandatory	Recipient number(s), comma-separated.
text	Mandatory	Message text (DLT-approved).
format	Optional	Response format: html / json / xml.
msgtype	Optional	Use 'unicode' for other languages.
group	Optional	Name of your contact group.
TID	Optional	DLT-approved template ID.
PEID	Optional	DLT-approved PEID.
schedule	Optional	Schedule time in dd/mm/YYYY hh:mm:ss format.

API Responses

✅ Message Submitted Successfully Message sent to the operator.
⚠️ Provide username and API key Fields are empty.
❌ Invalid username and API Key Wrong credentials.
❌ Sender ID Wrong!! Invalid or unauthorized sender ID.
❌ Undefined Route Incorrect route.
❌ Invalid Mobile Number Format issue or missing country code.
❌ Template Mismatch!! Message not approved for your account.
⚠️ No contacts available in this group Empty group.
⚠️ Please Assign Mobile Number Recipient number missing.
❌ Routing failed Error in routing.
⚠️ Provide Route Route not provided.
⚠️ Text Should not be an empty Message text is missing.
⚠️ Please check schedule date & time Schedule is invalid or in the past.
❌ Less balance / Insufficient credits Low credit balance.
⚠️ Sender id cannot be blank Sender ID missing.