Successive waves of migration over the course of several millennia have made Kochi a cultural melting pot. Despite the risk of overdevelopment, the city retains its distinct colonial heritage and a blend of tradition and modernity

Kochi was the centre of Indian spice trade for many centuries, and was known to the Yavanas (Greeks) as well as Romans, Jews, Arabs, and Chinese since ancient times.Kochi rose to significance as a trading centre after the port at Kodungallur (Cranganore) was destroyed by massive flooding of the river Periyar in 1341. The earliest documented references to Kochi occur in books written by Chinese voyager Ma Huan during his visit to Kochi in the 15th century as part of Admiral Zheng He's treasure fleet. There are also references to Kochi in accounts written by Italian traveller Niccolò Da Conti, who visited Kochi in 1440.

Kochi is located on the southwest coast of India spanning an area of 94.88 square kilometres. The city is situated at the northern end of a peninsula, about 19 kilometres long and less than one mile (1.6 km) wide. To the west lies the Arabian Sea, and to the east are estuaries drained by perennial rivers originating in the Western Ghats. Much of Kochi lies at sea level, with a coastline of 48 km.

The current metropolitan limits of Kochi include the mainland Ernakulam, old Kochi, the suburbs of Edapally, Kalamassery and Kakkanad to the northeast; Tripunithura to the south east; and a group of islands closely scattered in the Vembanad Lake. Most of these islands are very small, varying in extent from six square kilometre to less than a square kilometre.

Kochi is the economic capital of Kerala by volume of trade; though, unlike other South Indian cities, Kochi has been slow to industrialise. In recent years the city has rejuvenated from its economic stagnation and has witnessed heavy investment, thus making it one of the fastest-growing second-tier metro cities in India. The economy of the city can be classified as a business economy with emphasis on the service sector. Major business sectors include gold and textile retailing, seafood and spices exports, information technology (IT), tourism, health services, banking, ship building, and the fishing industry. The economy is mostly dependent on trade and retail activities. The city also houses Kerala's only bourse—the Cochin Stock Exchange.

Kochi is a major destination for IT and ITES companies, ranked by NASSCOM as the second-most attractive city in India for IT-based services. Availability of cheap bandwidth through undersea cables and lower operational costs compared to other major cities in India, has been to its advantage. Various technology and industrial campuses including the government promoted InfoPark, Cochin Special Economic Zone and KINFRA Export Promotion Industrial Park operate in the outskirts of the city. Several new industrial campuses for research, trade and development in biotechnology, electronic hardware and information technology are in various stages of construction in the suburbs of the city. Prominent among them are the Sobha Hi-tech city at Maradu and the SmartCity at Kakkanad, which on completion, would rank among the largest such ventures in the country. The Kochi International Trade and Exhibition Centre which is proposed at Kalamasserry, a suburb of Kochi, would rank among the tallest buildings in India at 500 meters (100 floors) upon completion. The Cochin International Airport is also in the process of setting up an aerotropolis at Nedumbasserry.

Public transport in the city is largely dependent on private buses. Taxis and auto rickshaws (called autos) are available for hire throughout the day.