A field-programmable gate array is an integrated circuit designed to be configured by a customer or a designer after manufacturing – hence the term "field-programmable". The FPGA configuration is specified using a hardware description language, similar to that used for an application-specific integrated circuit. Circuit diagrams were used to specify the configuration, but this is rare due to the advent of electronic design automation tools. FPGAs contain an array of programmable logic blocks, a hierarchy of "reconfigurable interconnects" that allow the blocks to be "wired together", like many logic gates that can be inter-wired in different configurations. Logic blocks can be configured to perform complex combinational functions, or simple logic gates like AND and XOR. In most FPGAs, logic blocks include memory elements, which may be simple flip-flops or more complete blocks of memory. Many FPGAs can be reprogrammed to implement different logic functions, allowing flexible reconfigurable computing as performed in computer software.

Contemporary field-programmable gate arrays have large resources of logic gates and RAM blocks to implement complex digital computations. As FPGA designs employ fast I/O rates and bidirectional data buses, it becomes a challenge to verify correct timing of valid data within setup time and hold time. Floor planning enables resource allocation within FPGAs to meet these time constraints. FPGAs can be used to implement any logical function; the ability to update the functionality after shipping, partial re-configuration of a portion of the design and the low non-recurring engineering costs relative to an ASIC design, offer advantages for many applications. Some FPGAs have analog features in addition to digital functions; the most common analog feature is a programmable slew rate on each output pin, allowing the engineer to set low rates on loaded pins that would otherwise ring or couple unacceptably, to set higher rates on loaded pins on high-speed channels that would otherwise run too slowly. Common are quartz-crystal oscillators, on-chip resistance-capacitance oscillators, phase-locked loops with embedded voltage-controlled oscillators used for clock generation and management and for high-speed serializer-deserializer transmit clocks and receiver clock recovery.

Common are differential comparators on input pins designed to be connected to differential signaling channels. A few "mixed signal FPGAs" have integrated peripheral analog-to-digital converters and digital-to-analog converters with analog signal conditioning blocks allowing them to operate as a system-on-a-chip; such devices blur the line between an FPGA, which carries digital ones and zeros on its internal programmable interconnect fabric, field-programmable analog array, which carries analog values on its internal programmable interconnect fabric. The FPGA industry sprouted from programmable read-only memory and programmable logic devices. PROMs and PLDs both had the option of being programmed in the field. However, programmable logic was hard-wired between logic gates. Altera was founded in 1983 and delivered the industry's first reprogrammable logic device in 1984 – the EP300 – which featured a quartz window in the package that allowed users to shine an ultra-violet lamp on the die to erase the EPROM cells that held the device configuration.

In December 2015, Intel acquired Altera. Xilinx co-founders Ross Freeman and Bernard Vonderschmitt invented the first commercially viable field-programmable gate array in 1985 – the XC2064; the XC2064 had programmable gates and programmable interconnects between gates, the beginnings of a new technology and market. The XC2064 had 64 configurable logic blocks, with two three-input lookup tables. More than 20 years Freeman was entered into the National Inventors Hall of Fame for his invention. In 1987, the Naval Surface Warfare Center funded an experiment proposed by Steve Casselman to develop a computer that would implement 600,000 reprogrammable gates. Casselman was successful and a patent related to the system was issued in 1992. Altera and Xilinx continued unchallenged and grew from 1985 to the mid-1990s, when competitors sprouted up, eroding significant market share. By 1993, Actel was serving about 18 percent of the market. By 2013, Altera and Xilinx together represented 77 percent of the FPGA market.

The 1990s were a period of rapid growth for FPGAs, both in circuit sophistication and the volume of production. In the early 1990s, FPGAs were used in telecommunications and networking. By the end of the decade, FPGAs found their way into consumer and industrial applications. Companies like Microsoft have started to use FPGAs to accelerate high-performance, computationally intensive systems, due to the performance per watt advantage FPGAs deliver. Microsoft began using FPGAs to accelerate Bing in 2014, in 2018 began deploying FPGAs across other data center workloads for their Azure cloud computing platform. In 2012 the coarse-grained architectural approach was taken a step further by combining the logic blocks and interconnects of traditional FPGAs with embedded microprocessors and related peripherals to form a complete "system on a programmable chip"; this work mirrors the architecture created by Ron Perloff and Hanan Potash of Burroughs Advanced Systems Group in 1982 which combined a reconfigurable CPU architecture on a single chip called the SB24.

Examples of such hybrid technologies

Martin C. Harty was an American politician, a member of the New Hampshire House of Representatives from 2010 to early 2011. A Republican, he was one of eight legislators who represent Strafford County District 3, comprising the towns of Barrington, Middleton, New Durham, Strafford. In March 2011, as a freshman State Representative, Harty promoted eugenics in a conversation with the manager of a community health program stating: "I'm sorry I don't agree with your side. I and several of us in the state house believe in eugenics... I think. So we believe that there is too many defective people... You know the mentally ill, the retarded, people with physical disabilities and drug addictions - the defective people society would be better off with out. I wish we had a Siberia so we could ship them all off to freeze to death and die and clean up the population. If you women didn't try to give yourself abortions, you wouldn't end up with defective children" He subsequently resigned, effective March 15, 2011.

Harty was 91 at the time of his resignation. He died in August 2017 at the age of 98

Chokwe Antar Lumumba is an American attorney, activist and the current Mayor of Jackson, Mississippi. While running for mayor, Lumumba soundly won the Democratic nomination, defeating incumbent mayor Tony Yarber and John Horhn, a state senator; as Jackson is a Democratic leaning city, Lumumba's primary victory was to make him the next mayor of Jackson. Lumumba was endorsed by Our Revolution and the Working Families Party, ran on a progressive platform promising to make Jackson "the most radical city on the planet." He is the son of former mayor Chokwe Lumumba, who served before his death in 2014. Lumumba has two children with Ebony. Lumumba received his bachelor's degree in political science and government from Tuskegee University and his J. D. degree from the Texas Southern University Thurgood Marshall School of Law. Lumumba was a featured speaker at the 2017 People's Summit. In the summer of 2018, Lumumba attended Michael Bloomberg's "Bloomberg Harvard City Leadership Initiative." In a press release, released by the City of Jackson, the Initiative was created by Bloomberg to train leaders to "manage the complexities of running a city, to have opportunities to learn from one another."

Four months in November, 2018, Bloomberg awarded the City of Jackson $1 million to create art highlighting the food insecurity crisis in Jackson. Lumumba was "overjoyed" his city was selected for the art project that will increase the "aesthetic appeal" amid the ongoing food insecurity crisis. In April, 2018, when the Jackson Zoo announced plans to consider moving from its current West Jackson location, Lumumba joined Working Together Jackson, the Zoo Area Progressive Partnership, Rosemont Missionary Baptist Church and other community groups, in an effort to prevent the zoo from moving and called the proposed plan disingenuous and disrespectful. During the dispute between Zoo leadership and the Lumumba administration, the Zoo contract expired and the facility was closed to the public for lack of licensing