It is the developer of the software distribution platform Steam and the game franchises Half-Life, Counter-Strike, Portal, Day of Defeat, Team Fortress, Left 4 Dead and Dota.

They entered the hardware market in 2015 with the Steam Machine, a line of gaming computers, which sold poorly, and released the HTC Vive and Valve Index VR headsets.

Most of Valve's revenue comes from Steam, which controlled over half of the digital PC games market in 2011 and generated an estimated $3.4 billion in 2017.

[14][15][16] With its realism, scripted sequences and seamless narrative, it had a lasting influence; according to IGN in 2014, the history of the FPS genre "breaks down pretty cleanly into pre-Half-Life and post-Half-Life eras".

[45] Media commentators speculated that Valve's transition to service provider with Steam, which generated an estimated $3.4 billion in 2017, had driven it away from game development.

[59][60] In November 2018, Valve released Artifact, a digital collectible card game based on Dota 2, with design by Richard Garfield, the creator of Magic: The Gathering.

[78] Initially, Valve used a hierarchical structure more typical of other development firms, driven by the nature of physical game releases through publishers that required tasks to be completed by deadlines.

"[56] In January 2023, People Make Games released a report on Valve's corporate structure and culture, based on interviews with several current and former employees.

They found that Valve's flat structure and stack-ranking compensation system created a poor release record and a lack of employee diversity.

[89] As part of Wolfire Games' lawsuit over Steam policies, case documents revealed details related to Valve's employee structure.

Valve has acknowledged the term, including tracking known discrepancies between ideal and actual releases on their public development wiki[91] and using it in announcements about such delays.

[96] Newell contrasted this approach to that of Warren Spector, whose open-ended games are designed to be replayed with different outcomes: "You spend all of this time to build stuff that most players will never ever ever see ...

[101][102] On August 1, 2012, Valve announced revisions to the Steam Subscriber Agreement (SSA) to prohibit class action lawsuits by users against the service provider.

[114][115] A precursor to such a unit is SteamOS, a freely available Linux-based operating system that builds upon the Steam client functionality that includes media services, live streaming across home networks, game sharing within families, and parental controls.

This would allow for "room-scale" VR experiences, where the player would not be required to remain in a stationary position in front of a camera and would be able to freely walk around the space.

Cisco and Valve intended to deliver a single dial-up service in Q1 2000 in the United States with a 30-day free trial with a bundled copy of Team Fortress modified to support PowerPlay.

[citation needed] In July 2013, Valve announced Pipeline, an intern project consisting of ten high school students working together to learn how to create video game content.

In addition to claims of copyright infringement, Valve asserted that Sierra breached contract by withholding royalties and delaying the release of Counter-Strike: Condition Zero until after the holiday season.

Vivendi and Sierra countersued, stating that Valve had misrepresented their position in the revised 2001 contract since they had been working on Steam at that point as a means to circumvent the publishing agreement.

The ruling stated that Vivendi Universal and its affiliates (including Sierra) were not authorized to distribute Valve games, either directly or indirectly, through cyber cafés to end users for pay-to-play activities pursuant to the parties' publishing agreement.

In addition, Judge Zilly ruled that Valve could recover copyright damages for infringements without regard to the publishing agreement's limitation of liability clause.

[137] In April 2009, Valve sued Activision Blizzard, which acquired Sierra Entertainment after a merger with its parent company, Vivendi Universal Games.

[137][138] Defense of the Ancients (DotA) was a landmark mod first released in 2003 that created the basis of the genre of multiplayer online battle arena (MOBA).

It was originally developed by Kyle Sommer (who goes by the alias Eul) within Blizzard Entertainment's Warcraft III: Reign of Chaos via its world editor, and spawned several similar efforts, notably DotA-Allstars.

[148] The High Court dismissed this claim in April 2018, asserting that Valve still was liable under Australian law since it sold products directly to its citizens.

[149] Consumer rights group UFC Que Choisir, based in France, filed a lawsuit against Valve in December 2015, claiming users should be able to resell their software.

[150][151] The High Court of Paris ruled in favor of UFC Que Choisir in September 2019, stating that Valve must allow the resale of Steam games.

[160] In January 2021, five gamers filed a proposed class-action antitrust lawsuit in California against Valve, alleging that the company "abuses the Steam platform's market power" by requiring game developers and publishers to enter into a 'most favored nation' agreement with Valve, restricting their ability to sell games for less on other platforms and thereby preventing price competition.

[166] In June 2024, Vicki Shotbolt, a children's digital rights activist, filed a lawsuit with the Competition Appeal Tribunal in the UK that accuses Valve of "rigging the market" for PC games, alleging that Valve used its market dominance to overcharge 14 million people in the UK and seeking damages of £22 to £44 per affected customer, or £656 million in total.

Valve also brought suit against a litigation financier for Zaiger over the funding of a social media campaign to recruit Steam users as clients.