Founded in 2009 by algorithm designer Sean Costello and visual designer Kristin Costello, Valhalla DSP is a Seattle, Washington-based audio software company specializing in digital reverb and delay plugins. Sean Costello developed the company's code library from scratch after a career designing audio algorithms at Staccato Systems and Analog Devices. The company has earned a reputation for producing studio-quality effects at an accessible $50-per-plugin price point, with several plugins offered completely free.

Valhalla DSP's product line includes ValhallaVintageVerb, which emulates the character of late 1970s and 1980s digital hardware reverbs; ValhallaRoom, an algorithmic reverb with eleven original algorithms spanning tight ambiences to vast modulated spaces; ValhallaPlate, which recreates the warm, dense sound of 1960s and 1970s plate reverbs; ValhallaShimmer, known for ethereal pitch-shifting reverb textures; and ValhallaDelay, which covers tape-style and digital echo effects. The free ValhallaSupermassive plugin has become widely popular for its massive reverbs and harmonic echoes, while ValhallaFreqEcho and ValhallaSpaceModulator round out the free offerings. ValhallaFutureVerb, featuring eight original reverb modes and twelve echo modes, represents the company's most advanced reverb engine.

The plugins are available in VST and AU formats and are used across a wide range of genres in professional and home studios alike. Adele's producer used ValhallaVintageVerb on tracks including "Hello" and "Water Under the Bridge," and the plugins appeared on Lana Del Rey's album Lust for Life.

Valhalla has 6 products cataloged on Equipboard, including Reverb Plugins, Flanger Plugins, and Delay Plugins. Their gear is featured by 93 artists, with the strongest followings in Electronic, Pop, and Rock. Notable users include Fred again.., Mike Shinoda, and Charlie Puth.