KRL Commuterline, commonly known as Greater Jakarta Commuter rail, Jakarta Commuter rail, and KRL Commuter Line Jabodetabek is a commuter rail system for Greater Jakarta in Indonesia. It was previously known as KRL Jabodetabek. It is operated by KAI Commuter (KAIC), a subsidiary of the Indonesian national railway company PT Kereta Api Indonesia (KAI). The rail system uses rolling stock of rapid transit standard and operates high frequency services with minimum headway. In 2019, the average number of Commuterline users per day reached 1.04 million, with the record of the highest number of users served in a day being 1,154,080.

"KRL" itself stands for "Kereta Rel Listrik" (literally "electric rail train" or "electric railcar"), a term for an electric multiple unit train.

In 1917, a plan to introduce electric railways in what was then Batavia was made by Dutch colonial railway company Staatsspoorwegen. A railway between Tanjung Priok to Meester Cornelis (Jatinegara) was the first line to be electrified, becoming the first narrow gauge electric railway service in Southeast Asia. The construction began in 1923 and completed on 24 December 1924. The line was opened on 6 April 1925—in time for the SS 50th anniversary—with 3000-series locomotives from SLM–BBC (Swiss Locomotive and Machine Works – Brown Boveri & Cie), 3100-series electric locomotives from AEG Germany, 3200-series electric locomotives from Werkspoor Netherlands and passenger coaches, as well as 30 ESS 100/200/400 EMU passenger motor and trailer cars, all manufactured for the railway by Westinghouse and General Electric.

The electrification project continued and on 1 May 1927, all rail lines that surround Batavia had been fully electrified. Batavia Zuid station (now Jakarta Kota) was temporarily closed in 1926 and was reopened on 8 October 1929 to accommodate the new electric motive power that by then had become an envy of the region, which by then had been dominated by steam. The last part of the electrification project, Batavia Zuid – Buitenzorg (Bogor), was completed in 1930. After independence in 1945, in periods before and after a brief return to Dutch government control for the network and also a 4-year Japanese operation of the railways during the Second World War, the Jakarta electric railway fell under the supervision of the new Indonesian government thru DKARI (Djawatan Kereta Api Repoeblik Indonesia, Indonesian Railways Service, former name of the present KAI), with Indonesian personnel controlling its assets. The city's growth postwar led to the network becoming the nation's true first commuter rail service, combined with steam and later on diesel powered commuter trains serving the capital and its suburbs.

Transportation in Jakarta was at its lowest point during the 1960s. Tramways in Jakarta were closed in 1960 and railway traffic on Manggarai – Jakarta Kota was restricted in November 1966. In 1965, a portion of railway line between Gondangdia and Sawah Besar was stripped from electrification, with remaining services on the portion now powered by steam and diesel trains. It was reported that then-President Sukarno wanted to get rid of anything that would block the view of Monas and Merdeka Square, then still under construction. After Sukarno's fall, the electrification was later reconstructed and was formally reopened in 1970 sans the EMUs, two converted into diesel railbuses, the rest into locomotive hauled trains for the steam and diesel traction of the capital commuter runs, as well as the remaining electric locomotives from the 1920s.

On 16 May 1972, The National Railway Corporation of Indonesia (Perusahaan Negara Kereta Api/PNKA, successor of DKA), as part of the festivities for the 47th anniversary of the electric railways, finally ordered 10 new sets of electric multiple units from Japan, leading to the revival of the electric train services within Greater Jakarta. The new trains, built by Nippon Sharyo, arrived in 1976 - as a belated gift for the Golden Jubilee of the commuter train services the previous year, 1975 - and replaced the old locomotives and locomotive-hauled coaches on the then electric lines, driven by the then ongoing rehabilitation efforts on the rest of the network and funding that precipated another round of expansion into the suburbs of the capital. These EMU sets consisted of four cars each, with capacity of 134 passengers per car. Those new trains (commonly known as EMU Rheostatik) will continue serving the passengers in Jakarta for the next 37 years. PNKA continued importing trains from Japan, South Korea, Belgium and Netherlands until the late 1990s, while it also accepted Indonesian builds by local manufacturer Industri Kereta Api beginning 1987. By the 1990s, Greater Jakarta commuter rail used a mixture of EMUs and DMUs, with lines waiting for electrification used Japan-made DMUs (class MCW 302) or diesel locomotive-hauled commuter coaches. It was on the non-electrified network where the 1987 Bintaro train crash occurred, the biggest single tragedy not just of the commuter network, but of the then Indonesian Railways Service Corporation LLC (Perusahaan Jawatan Kereta Api, PJKA, later on Perusahaan Umum Kereta Api or Permuka, the Indonesian Railways Public Corporation LLC) as a whole, spurring an era of change across the entire national rail network, and not just on the commuter services and the trainsets used in this venture. This happened just 3 years before the formal debut of electric commuter express services on the then active lines, that began in 1990 as part of the 65th anniversary of the electric commuter rail system, and before parts of the line from Jakarta Kota south to Gambir were changed from ground level to elevated tracks in 1991-92. Yet another train collision in the network in 1992 - this time in the Bogor main line - resulted in much of the rest of said line being double tracked.

In May 2000, the government of Japan via JICA and Tokyo Metropolitan Government donated 72 units of used Toei 6000 trains, formerly operating on Toei Mita Line. These were the first air-conditioned electric trains in Indonesia. The new trains were operated on 25 August 2000 for express services.

The current form of electric train service in Jakarta was begun in 2008. Jabotabek Urban Transport Division, a sub-unit of KAI that handles commuter service around Jabodetabek, spun-off to form KAI Commuterline Jabodetabek (KCJ). Ticket revenues, rolling stock maintenance, and station management was transferred to the newly formed subsidiary, but all operational matters (e.g. scheduling and dispatching), rolling stock, stations and infrastructures remained under KAI responsibility. At the same time, all track matters and station construction and maintenance were handled by the Ministry of Transportation.