  We describe a general purpose digital servo optimized for feedback control of
lasers in atomic, molecular, and optical (AMO) physics experiments. The servo
is capable of feedback bandwidths up to roughly 1~MHz (limited by the 320~ns
total latency); loop filter shapes up to fifth order; multiple-input,
multiple-output control; and automatic lock acquisition. The configuration of
the servo is controlled via a graphical user interface, which also provides a
rudimentary software oscilloscope and tools for measurement of system transfer
functions. We illustrate the functionality of the digital servo by describing
its use in two example scenarios: frequency control of the laser used to probe
the narrow clock transition of $^{27}$Al$^+$ in an optical atomic clock, and
length control of a cavity used for resonant frequency doubling of a laser.
