The Songhai empire's economy was primarily trade based. They were rich in salt and gold, which drew many other empires and leaders to them.
Songhai traded with the Muslims and Berbers towards the north.
Due to the convenient presence of the Niger River, trade along the river flourished, and the Songhai became accomplished in the way of the water.
Gao, the capital of the Songhai Empire, was a major center of trade, and was extremely prevalent in the flourishing trade of the Songhai empire. It was so influential that leaders of the Mali empire noted the importance of this budding economy.
This led to Gao being strongly fortified
Many trade ports were located in the cities of the Songhai empire, where goods such as kola nuts, gold, ivory, slaves, spices, palm oil, salt, cloth, arms, horses and copper were traded between the Muslim's and the Songhai.
One of the major trade routes that the Songhai used was the Trans - Saharan trade route, and with two major cities along this trade route (Djenne and Timbuktu), they were able to effectively use this route