Neither model includes a fingerprint reader; facial recognition (using a dot projector, infrared emitters and cameras along the top bezel of the device) is the only biometric authentication method offered by the Pixel 4.

[19] Both models use the Qualcomm Snapdragon 855 system-on-chip (consisting of eight Kryo 485 CPU cores, an Adreno 640 GPU and a Hexagon 690 DSP), with 6 GB of LPDDR4X RAM.

[21] The Pixel 4 features an OLED display manufactured by Samsung[22] with HDR support, that operates at a refresh rate of up to 90 Hz; it dynamically adjusts depending on content to preserve battery life.

[18][28][29] Due to its use of 60 GHz frequency bands, Google was required to obtain specific regulatory approval for the radar system in all countries that the Pixel 4 is being sold.

Google stated that it had no plans to sell the Pixel 4 in India, with the company officially stating a preference to continue marketing the Pixel 3a in the region; media outlets noted that civilian use of the 60 GHz frequency is prohibited in India, unlike in the U.S. and some other countries, where it is considered unlicensed spectrum.

[18] After Google demonstrated astrophotography sample photos, a scene of San Francisco with the Moon blown out and the woods underexposed was shown.

Marc Levoy explained that the difference in light between the Moon and woods was too significant, requiring 19 stops of dynamic range which no phone or DSLR camera was currently capable of performing.

He reaffirmed Google's commitment to improving the camera with software updates (a signature of the Pixel line) and said to stay tuned.

[43][44] Ars Technica gave the device a mixed pre-release review, noting that the etched finish of the orange and white models felt stronger than that of the Pixel 3 without compromising its "soft" and "grippy" feel, but that the screen bezels looked "lopsided".

The Motion Sense system was panned for its reliance on hand waving gestures that were "so big that it's a cumbersome, tiring, annoying thing to do."

This was contrasted with early demonstrations of the technology being able to detect "sub-millimeter motions at high speed and accuracy", noting that Google's admitted need to downsize the radar chip in order to fit into a smartphone may have compromised its capabilities.

[16] Ars Technica's in-depth review concluded that "This year, the Pixel 4 feels like a bunch of software decisions designed to prop up hardware that has been cost-cut to death".