The Interface Region Imaging Spectrograph (IRIS) instrument is a multi-channel imaging spectrograph with a 20 cm UV telescope. IRIS obtains spectra along a slit (1/3 arcsec wide), and slit-jaw images. The CCD detectors have 1/6 arcsec pixels. IRIS has an effective spatial resolution between 0.33 and 0.4 arcsec and a maximum field of view of 120 arcsec.

The far-ultraviolet channel covers 133.2-135.8 nm and 139.0-140.6 nm with a 4 nm resolution and an effective area of 2.8 square-cm. The near-ultraviolet channel covers 278.5-283.5 nm with a 8 nm resolution and an effective area of 0.3 square-cm. Slit-jaw imaging has four passbands: 133.5 nm and 140.0 nm with a 4 nm bandpass each; and 279.6 nm and 283.1 nm with a 0.4 nm bandpass each.

IRIS has a high data rate (0.7 Mbit/s on average) so that the baseline cadence is 5 s for slit-jaw images and 1 s for six spectral windows, including rapid rastering to map solar regions.