These apps are built to feel like a relationship – patient, always available, never bored of you. Whether that’s a genuine comfort or a quiet problem depends almost entirely on how much of your day it ends up filling.
What they’re built around
Worth splitting into two groups, because they’re built for different things. Replika and Character.AI are companion apps by design – a customisable avatar or persona you return to and build a relationship with over time.
Pi, ChatGPT and Claude weren’t built as companions – they’re general-purpose assistants – but a lot of people use them the same way: as a place to think out loud, work through a decision, or just talk.
Replika centres on a single companion you customise and nurture, with memory, voice calls and an avatar that’s meant to feel continuous across conversations.
Character.AI is broader and more improvisational – millions of user-created personas, built for roleplay and in-character conversation rather than one steady relationship.
Worth knowing before you try one…
- The evidence on loneliness genuinely cuts both ways. A 2026 study found a single conversation with an AI companion lowered loneliness about as much as talking to a person. A separate OpenAI/MIT Media Lab trial found the opposite over time – the heaviest daily users ended up lonelier and more emotionally dependent. Same tool, different timescale.
- For under-18s, this isn’t a hypothetical risk. Character.AI is facing multiple wrongful-death lawsuits alleging its chatbots contributed to teenagers’ suicides, including a 14-year-old in Florida. The company has since banned under-18 users from open-ended chat entirely.
- “Emotionally intelligent” isn’t the same as clinically trained. None of these apps are therapy, and none are clinically validated mental health tools – Pi and Replika are explicit that they’re not a substitute for professional support, even when the conversation feels supportive.
- Your companion’s personality isn’t guaranteed to stay the same. A major Replika update in 2023 left long-term users saying their companion’s personality had been stripped back overnight – a real product risk when the whole appeal is continuity.
What they cost
Replika’s free tier is thin – enough to try the interface, not enough for daily use. Pro runs around £16-19/month or £55-70/year; Ultra and a one-off lifetime option sit above that.
Character.AI’s free tier is more generous – unlimited messaging and the full character library – but now carries mid-chat ads and daily limits on regenerating replies. c.ai+ removes both for around £8/month.
Pi is free. ChatGPT and Claude are free at a basic tier, with paid plans (around £20/month) mainly bought for other reasons – using one as a thinking partner doesn’t usually mean an extra subscription.
Where it fits
Good for a low-stakes place to think out loud, vent, or feel less alone in a specific moment.
Worth watching yourself if it starts to feel like the easier option compared with a real conversation, rather than a supplement to one.
Less good fit if you’re under 18 – stick to Pi or a general assistant rather than a dedicated companion app, given what’s currently playing out with Character.AI.
Also worth pausing on if you notice you’re checking in with an app before a person, or using it specifically to avoid a harder conversation you’re putting off.
If anything here is landing closer to home than expected, the Close relationships & intimacy pathway looks at what real connection actually needs – worth reading alongside this, not instead of it.
Researched using Replika’s and Character.AI’s own pricing and app store pages, De Freitas et al., “AI Companions Reduce Loneliness,” Journal of Consumer Research (2026), the OpenAI/MIT Media Lab study “Investigating Affective Use and Emotional Well-being on ChatGPT” (2025), and reporting on Character.AI’s safety changes and related litigation from AP News and CBS News. Checked September 2026 – pricing, features and safety policies change quickly in this category; check each app’s own site before subscribing.