Amazon SQS (Simple Queue Service) is described as 'Amazon Simple Queue Service (SQS) is a fast, reliable, scalable & affordable message queuing service. Use SQS to transmit data without losing messages' and is an website in the Network & Admin category. There are seven alternatives to Amazon SQS (Simple Queue Service), not only websites but also apps for a variety of platforms, including Windows, Linux, Mac and SaaS. The best alternative is RabbitMQ, which is both free and Open Source. Other great sites and apps similar to Amazon SQS (Simple Queue Service) are mosquitto (Free, Open Source), ActiveMQ (Free, Open Source), Ralley (Freemium) and Qutrunk (Free).
Eclipse Mosquitto is an open source (EPL/EDL licensed) message broker that implements the MQTT protocol versions 5.0, 3.1.1 and 3.1. Mosquitto is lightweight and is suitable for use on all devices from low power single board computers to full servers.