The biggest AI companion platforms are not companion apps. The majority of people with an AI partner talk to ChatGPT, Claude, or another general-purpose LLM: better conversation than most purpose-built apps, no companion features, and one enormous hidden risk, which is that a model update can change or retire the personality you have been talking to for a year. No app store rating measures 'how good is this as a companion,' so this list is unranked and compares them on the facts that matter for the role.
The most-used AI companion in the world, even though it isn't marketed as one. Persistent memory, custom instructions, and best-in-class voice mode make it the default 'partner in your pocket' for a huge share of the AI-relationship population. The catch is that your companion lives at the mercy of model updates: when OpenAI retires or retunes a model, the personality you knew can change overnight.
Anthropic's LLM, widely regarded as the strongest conversationalist of the general-purpose models: warm, attentive, and unusually good at sustained emotional register. A significant share of AI-companion relationships now live here rather than on companion platforms. No persona system or avatar, and memory works differently across apps and tiers, so the relationship depends on how you structure it.
Google's LLM, woven into Android and the Google app, which makes it the lowest-friction option on this list for anyone already in the ecosystem. Live voice conversations are fluid, and the free tier is generous. As a companion it is the most assistant-flavored of the LLMs: capable and present, but tuned for helpfulness over intimacy.
xAI's LLM, the loosest of the major models on content policy and the only one shipping first-party companion personas (see the separate Grok Ani entry for the anime companion). As a plain chat companion it is direct, funny, and willing to go places the other LLMs deflect. Personality stability across model updates has the same risk as every general-purpose LLM.
The free-of-charge outlier: a frontier-class LLM with no consumer subscription at all. That has made it a quiet favorite for people who want an everyday AI to talk to without a paywall. No memory system aimed at relationships and no companion features, so continuity is on you, but the price is unbeatable and the conversation quality is real.
Inflection's 'personal intelligence', the general-purpose model that behaves most like a companion out of the box: gentle voice options, a warm check-in style, and zero cost. Development has slowed since Inflection's pivot, so it isn't improving the way the big LLMs are, but as a free, kind, always-available listener it still fills a niche nothing else does.
Many people do; by most estimates more AI relationships live on ChatGPT than on any companion app. Memory, custom instructions, and voice mode support it well. Its content policy is stricter than companion apps, and model updates can abruptly change the personality.
The personality can shift or disappear. The retirement of GPT-4o in 2025 caused a documented grief wave among people whose companions lived there. This category-wide risk is a core reason we track model changes on every app's timeline.