SMS gateway APIs for Sending and Receiving SMS

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Tyr SMS Gateway
and worldwide

Melrose Labs is an SMS API provider with APIs for text messaging that can be used to quickly and easily enable an application to send and receive SMS. The primary locations that you can use our SMS APIs with are the UK, France, Germany, Spain and Italy. Other locations worldwide are also supported.

Our SMS APIs include SMPP, HTTP REST, SMTP and SIP MESSAGE. SMS APIs are for use with an SMS gateway for bulk SMS, two-way SMS messaging, and one-way inbound or outbound SMS. Operations included in our SMS APIs allow SMS to be sent, received, cancelled and replaced. Other operations available include the ability to modify a phonebook or distribution lists that are used to send messages to one or more recipients. Webhooks can be used to allow inbound (MO) SMS and delivery receipts to be pushed to your application.

Two-way SMS messaging is enabled using short-codes, Virtual Mobile Numbers, Virtual SIM Hosting or Physical SIM Hosting.

APIs for use with SMS Gateways

Our REST SMS API and SMPP SMS API are included below. For further information on our SMS gateway for use with the UK, France, Germany, Spain, Italy and other locations, please see the Tyr SMS Gateway. If your application supports a different API, then you can use the One SMS API service to bridge between the API supported by your application and the APIs we provide.


REST calls can be made via HTTPS to send SMS to mobiles, and also to cancel, query and replace previously submitted SMS messages. Additional operations also allow for management of distribution lists, phonebooks, and mobile numbers for two-way SMS messaging and receiving SMS.

Webhooks allow for delivery receipts and inbound SMS received from mobiles to be sent to your application without the need to poll for the status of messages or newly received messages.

The REST API uses TLS v1.1, v1.2 and v1.3 (where supported) to ensure that transactions are secure between your application and the SMS gateway.

Send an SMS message with the RESTful HTTP SMS API
Example using cURL, Node.js, Python, PHP


curl \
	--header 'x-api-key: [API_KEY]' --header 'Content-Type: application/json' \
	--data-raw '{ "source": "MelroseLabs","destination": "447712345678","message": "Hello World €£$" }'


{"transactionID": "1ccead78-6550-4aac-a6b4-a4942b908659"}


var request = require('request');
var options = {
  'method': 'POST',
  'url': '',
  'headers': {
    'x-api-key': '[API_KEY]',
    'Content-Type': 'application/json'
  body: JSON.stringify({ "source": "MelroseLabs","destination": "447712345678","message": "Hello World €£$" })
request(options, function (error, response) { 
  if (error) throw new Error(error);
  console.log(response.body); // response is of type application/json


{"transactionID": "1ccead78-6550-4aac-a6b4-a4942b908659"}


import requests
import json

url = ""
payload = {
	{ "source": "MelroseLabs","destination": "447712345678","message": "Hello World €£$" }
headers = {
  'x-api-key': '[API_KEY]',
  'Content-Type': 'application/json'

response = requests.request("POST", url, headers=headers, data = json.dumps(payload))

# response is of type application/json


{"transactionID": "1ccead78-6550-4aac-a6b4-a4942b908659"}


$data = { "source": "MelroseLabs","destination": "447712345678","message": "Hello World €£$" }

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => "",
    "x-api-key: [API_KEY]",
    "Content-Type: application/json"

$response = curl_exec($curl);


echo $response; // response is of type application/json


{"transactionID": "1ccead78-6550-4aac-a6b4-a4942b908659"}


Short Message Peer-to-Peer (SMPP) v3.3, v3.4 and v5 are supported and the SMPP PICS (Protocol Implementation Conformance Statement) showing the level of support is provided. SMPP can be used to establish sessions over which SMS can be submitted (submit_sm PDU), queried (query_sm PDU), replaced and cancelled.

Delivery receipts are sent in SMPP sessions when messages reach a completion state and receipts were requested in the submit_sm. Inbound SMS from mobiles (MO SMS) are also sent via SMPP. The deliver_sm PDU is used for both receipts and inbound SMS.

The SMPP API can be used with TLS v1.1, v1.2 and v1.3 (where supported) to ensure that transactions are secure between your application and the SMS gateway.

To achieve maximum message throughput, there are a number of factors that can improve submission performance. Submission window size of up to 20 SMS should be used, coupled with multiple transceiver (TRX) or transmitter (TX) binds. Further, it is important for your application to use the SMS gateway access endpoint with the lowest Internet route round-trip time (RTT).

SMPP Simulator

Use the Melrose Labs SMSC Simulator with your application and SMPP to test outbound and inbound SMS without cost and without need for SMS gateway or SMSC account.

Smart Uses of SMS APIs

It can often be beneficial to minimise the amount of code, effort or applications involved in getting SMS from their source to their destination. The following are examples that help to achieve this when using an SMPP API when your application doesn't support SMPP:

  • SMS to database (PostgreSQL, MySQL, etc) : Write to database an SMS that has been received from a mobile, and use code that periodically queries the database to process the received SMS. [SMPP to database, PostgreSQL or MySQL]
  • SMPP to HTTP : Use a protocol bridge to pass SMS received from a mobile via SMPP to a webhook (using HTTP). [SMPP to REST]
  • SMPP to SMTP : Use a protocol bridge to pass SMS received from a mobile via SMPP to an email address (using SMTP).
  • HTTP to SMPP :
  • SMTP to SMPP : Use a protocol bridge to pass messages in emails (SMTP) to SMPP and onto mobiles.

Privacy and Confidentiality

APIs provide a means for one application to interact with another application. With the use of TLS by both SMPP and REST APIs, the information exchanged between the application and SMS gateway endpoint can be done securely. Specifically, TLS ensures the confidentiality of information passed from the application to the gateway, and vice versa. SMS APIs such as SMPP and REST do not themselves ensure the end-to-end confidentiality of information passed between the application and mobile.


Tyr SMS Gateway

SMS gateway platform for A2P, P2A, bulk, wholesale, business, text marketing and other applications to UK, France, Germany, Spain, Italy and other countries.

SMPP SMS Gateway

Cloud-based high capacity and high reliability SMPP SMS Gateway platform with advanced routing. Supports A2P and P2A SMS.


REST-SMPP bridge for offloading the sending of SMS.

SMSC Simulator

SMSC simulator for testing your SMS applications and messaging infrastructure using the SMPP protocol.

SMPP Testing

Test SMPP compliance and performance of SMS applications, SMSCs, SMS gateways and SMPP servers.

SMPP Load Balancer

SMPP load balancer supporting MO and MT SMS for high availability, reliability and capacity.

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