Enshittification, also known as platform decay, is a process in which two-sided online products and services decline in quality over time. Initially, vendors create high-quality offerings to attract users, then they degrade those offerings to better serve business customers, and finally degrade their services to both users and business customers to maximize short-term profits for shareholders.

Canadian writer Cory Doctorow coined the neologism enshittification in November 2022. The American Dialect Society selected it as its 2023 Word of the Year, with Australia's Macquarie Dictionary following suit for 2024. Merriam-Webster and Dictionary.com also list enshittification as a word.

Doctorow advocates for two ways to reduce enshittification: upholding the end-to-end principle, which asserts that platforms should transmit data in response to user requests rather than algorithm-driven decisions; and guaranteeing the right of exit—that is, enabling a user to leave a platform without losing access to data, which requires interoperability. These moves aim to uphold the standards and trustworthiness of online platforms, emphasize user satisfaction, and encourage market competition.

Cory Doctorow first used enshittification as a descriptor of service degradation and formalized its meaning in a November 2022 blog post that was republished three months later in Locus. He expanded on the concept in another blog post that was republished in the January 2023 edition of Wired:

Here is how platforms die: first, they are good to their users; then they abuse their users to make things better for their business customers; finally, they abuse those business customers to claw back all the value for themselves. Then, they die. I call this enshittification, and it is a seemingly inevitable consequence arising from the combination of the ease of changing how a platform allocates value, combined with the nature of a "two-sided market", where a platform sits between buyers and sellers, hold each hostage to the other, raking off an ever-larger share of the value that passes between them.

In a 2024 op-ed in the Financial Times, Doctorow argued that "'enshittification' is coming for absolutely everything" with "enshittificatory" platforms leaving humanity in an "enshittocene".

Doctorow argues that new platforms offer useful products and services at a loss, as a way to gain new users. Once users are locked in, the platform then offers access to the userbase to suppliers at a loss; once suppliers are locked in, the platform shifts surpluses to shareholders. Once the platform is fundamentally focused on the shareholders, and the users and vendors are locked in, the platform no longer has any incentive to maintain quality. Enshittified platforms that act as intermediaries can act as both a monopoly on services and a monopsony on customers, as high switching costs prevent either from leaving even when alternatives technically exist. Doctorow has described the process of enshittification as happening through "twiddling": the continual adjustment of the parameters of the system in search of marginal improvements of profits, without regard to any other goal. Enshittification can be seen as a form of rent-seeking.

To solve the problem, Doctorow has called for two general principles to be followed: