There are several free SMS APIs available for sending text messages programmatically. However, many of these services have usage limits, and may not be suitable for large-scale or commercial use. Here are a few options for free SMS APIs:

1. 1. Twilio: Twilio is a popular cloud communications platform that provides APIs for sending SMS, voice, and video messages. They offer a free trial, which includes a certain number of free SMS messages, but after that, you need to pay for the service.

2. 2. Nexmo: Nexmo is a cloud communication platform that provides APIs for sending SMS, voice, and other messaging services. They offer a free trial, which includes a certain number of free SMS messages, but after that, you need to pay for the service.

3. 3. Free SMS Gateway: This is a free online SMS service that allows you to send text messages to mobile numbers worldwide. They have a certain number of free SMS per day, but it's not guaranteed to work for all countries.

4. 4. Textbelt: Textbelt is a simple, free SMS API for sending text messages. It allows you to send a limited number of messages per day.

5. 5. Telesign: Telesign offers a free SMS API for sending text messages. They have a limited number of free SMS messages per month.

Please note that these services have usage limits, and may not be suitable for large-scale or commercial use. You should check their terms and conditions before using them. Additionally, you should also be aware that there may be additional costs for sending messages to certain countries or carriers.