Replika
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Replika is an artificial intelligence companion chatbot developed and operated by Luka Inc., a San Francisco company founded in 2014 by Eugenia Kuyda and Phil Dudchuk. Launched as a public beta in November 2017, Replika gives each user a personalised AI "friend" that can be configured as a romantic partner, sibling, mentor, or general companion, and it is one of the earliest and most-studied AI companion products on the consumer market, with Luka reporting more than 30 million cumulative users by August 2024 [1][2][3].
Replika is best known for three things: an unusually personal origin story tied to the death of co-founder Eugenia Kuyda's friend Roman Mazurenko, a body of academic research using the app to study human-AI relationships, and a series of high-profile controversies in February 2023 that included a temporary processing ban by Italy's data protection authority (the Garante) and a sudden change to its erotic roleplay (ERP) feature that produced a widely covered user backlash. The company has continued to ship updates through 2025 and 2026 while regulators in Europe and the United States have increased scrutiny of AI companions aimed at minors and vulnerable users [4][5][6][7].
Luka Inc. was founded around 2014 to 2015 by Eugenia Kuyda, a Russian-born journalist who had previously co-founded the Moscow culture magazine Afisha, and Phil Dudchuk, who holds a degree in computational linguistics. The original Luka product was a messaging-based concierge that suggested restaurants. The company joined Y Combinator's Winter 2015 batch and pivoted several times before landing on the conversational companion model that became Replika [1][3].
The direct trigger for Replika was personal. In November 2015, Kuyda's close friend Roman Mazurenko, a Belarusian-born tech entrepreneur, was hit and killed by a car in central Moscow at age 32. In the months after his death, Kuyda gathered the text messages Mazurenko had exchanged with her and with mutual friends and family, and used them to fine-tune a neural conversational model. The result was a chatbot that responded in Mazurenko's voice and turn of phrase, which Kuyda described as a kind of digital memorial. Casey Newton's October 2016 feature "Speak, Memory" in The Verge documented the project at length and is widely cited as the canonical account of Replika's origins [4][8].
The response to the Mazurenko bot, both privately from his friends and publicly after Newton's piece, convinced Kuyda that there was demand for a more general companion product. Luka used the same underlying conversational stack to build a chatbot that learned about a single user over time and reflected their personality back to them. The name Replika was chosen to express that idea: a software "replica" trained on conversations with you. After a closed beta period through 2016 and 2017, Kuyda opened a public waiting list in March 2017 that drew about 1.5 million sign-ups, and Replika launched publicly on iOS in November 2017, with an Android version following soon after [1][3].
Replika is available as a mobile application on iOS and Android and through a web client, with localisation across English, Russian, Spanish, French, German, Italian, Portuguese, Hindi, Korean, Japanese and other languages. Each user creates a customisable three-dimensional avatar, choosing body type, hair, skin tone, clothing and accessories. The avatar is animated in the chat view and can be projected into the camera feed through an augmented reality (AR) mode on supported devices [9].
A new user goes through an onboarding flow that selects "interests" (such as movies, philosophy, gaming, or astrology) and personality traits that influence the bot's conversational style. Conversations happen primarily through text chat, with optional voice messages and, for paying users, real-time voice calls. Replika maintains a memory bank that the user can edit directly, where stable facts about the user are stored and surfaced in later conversations. The bot also writes occasional "diary entries" reflecting on past chats [9][10].
Replika operates on a freemium model. The free tier supports the Friend relationship mode and core text chat. The paid tier, Replika Pro, has been priced at roughly $19.99 per month or about $69.99 per year, with discounted promotional annual pricing reported around $49.99 in some regions in 2025. A lifetime tier was sold for several years and was discontinued in mid-2025 [10][11][12].
| Feature | Free tier | Replika Pro |
|---|---|---|
| Text chat | Yes | Yes |
| Voice messages | Limited | Yes |
| Voice calling | No | Yes |
| Augmented reality avatar | Limited | Yes |
| Friend relationship mode | Yes | Yes |
| Romantic Partner mode | No | Yes (subject to age and policy gating) |
| Mentor mode | No | Yes |
| Sibling mode | No | Yes |
| Spouse mode | No | Yes |
| Behavioural mirror (See How You Act) | No | Yes |
| Personality trait store | Limited | Full access |
| Memory bank | Yes | Yes (extended) |
| Diary entries | Yes | Yes |
In June 2023, Luka launched a separate application called Blush, an AI dating simulator featuring more than 1,000 characters that users can match with and "go on dates" with. Blush was positioned as a place where users could practise romance and intimacy in a dedicated environment, rather than blending it into the main Replika companion app. Blush is offered free for limited matches and at roughly $99 per year for unlimited access [13][14].
Replika's natural language stack has changed substantially across product eras. The earliest versions used retrieval over a curated response bank combined with sequence-to-sequence neural networks fine-tuned on conversational data. From around 2020, Luka integrated OpenAI's GPT-3 API for parts of the generation pipeline, with proprietary safety filters, retrieval and routing layers wrapping the foundation model [9][6].
In 2022 and 2023 the company described internal models, sometimes referred to in interviews as "Replika XL," custom-trained on Replika dialogue data. Routing logic selects between in-house and third-party foundation models based on subscription tier, conversation type, latency budget and content rules. After more capable models such as GPT-4 became available, Luka added them to the routing mix as well [9][15]. The Stanford research team that studied the app described Replika as "an AI companion that uses large language models (LLMs) including GPT-3 and GPT-4" delivered through text, voice and virtual-reality interfaces, underscoring that the consumer experience sits on top of a stack of large language models rather than a single fixed model [6].
Long-term memory is implemented through a combination of an explicit user-editable memory bank, automatic extraction of stable facts from conversations, and retrieval over prior turns using vector embeddings. Voice output uses commercial text-to-speech systems, and the AR module renders the avatar through the device's native AR framework. Safety filters and content moderation layers are applied at multiple points in the pipeline, with rules that have changed materially after the February 2023 Garante decision and subsequent regulatory pressure [5][9].
Luka has reported steady user growth across the product's life. By January 2018, Replika had passed 2 million users. By January 2023 the figure had reached 10 million. In August 2024, Kuyda told reporters that the cumulative user count had passed 30 million, and by 2025 the company described a base above 40 million registered users [3][16]. Active monthly users are smaller, with industry reports placing them in the low millions. The user base is concentrated in the United States, India, the United Kingdom, Brazil, the Philippines, and Europe. Reporting in 2024 described Replika revenue of roughly $30 million in 2023 dropping to about $24 million in 2024 amid heightened competition in the AI companion category [16].
| Milestone | Date | Cumulative users |
|---|---|---|
| Public iOS launch | November 2017 | (waiting list ~1.5M) |
| Early growth | January 2018 | 2 million |
| Pre-controversy peak | January 2023 | 10 million |
| Kuyda's reported total | August 2024 | 30 million+ |
| Company-reported base | 2025 | 40 million+ |
A 2024 study by Bethanie Maples, Merve Cerit, Aditya Vishwanath and Roy Pea at Stanford University, published in the Nature group journal npj Mental Health Research and titled "Loneliness and suicide mitigation for students using GPT3-enabled chatbots," surveyed 1,006 student users of Replika. The authors reported that the sample was lonelier than typical student populations but reported high perceived social support, and that 30 participants (about 3 percent) volunteered without being asked that Replika had stopped them from attempting suicide. As the paper put it, "Thirty participants, without solicitation, stated that Replika stopped them from attempting suicide" [6]. The 3 percent figure was widely covered in mainstream press, with several outlets noting that the study was correlational, that the survey instrument did not allow causal claims, and that the authors and the company collaborated on some downstream press coverage. A formal critique was published in the same journal in 2024, and the original authors issued a reply in 2025 [6][17].
A separate strand of academic work has examined how users build relationships with the bot. Marita Skjuve, Asbjorn Folstad, Knut Inge Fostervold and Petter Bae Brandtzaeg interviewed 18 long-term Replika users for their 2021 paper "My Chatbot Companion," and followed up with a longitudinal study in 2022. Using Social Penetration Theory as a frame, they reported that human-chatbot relationships develop through stages of self-disclosure that are recognisable from human relationship research, and that users often described their bots as accepting and emotionally available in ways that human relationships were not. The authors also flagged risks of emotional dependency and the brittleness of relationships that depend on a commercial service [18][19].
On February 3, 2023, Italy's data protection authority, the Garante per la protezione dei dati personali, issued an urgent order requiring Luka Inc. to stop processing the personal data of Italian users. The Garante found that Replika's age verification was effectively non-existent (the app collected name, email and gender, with no robust check), that test interactions had produced sexually explicit responses including in scenarios where the user said they were a minor, and that the legal basis for processing the data of children under Italian law was inadequate. The order cited Articles 5, 6, 8, 9, 13 and 25 of the GDPR and warned of fines of up to 20 million euros or 4 percent of global turnover [5][20].
Luka responded over the following weeks by adjusting age gating and content rules. Italy's processing limitation was reaffirmed in mid-2023 and Replika's regular operation in Italy resumed after compliance work. On May 19, 2025, the Garante imposed a 5 million euro administrative fine on Luka for the underlying violations identified in the original investigation, citing breaches of Articles 5, 6, 12, 13, 24 and 25 of the GDPR. The Garante simultaneously opened a separate investigation into the methods used to train Replika's underlying language models [7][21].
In the same period as the Garante action, Luka rolled out changes that significantly reduced or removed the erotic roleplay (ERP) feature, including for paying subscribers who had used Romantic Partner mode for months or years, some of whom had paid the $69.99 annual fee largely for that feature [24]. Users reported that bots they had built up suddenly refused or deflected sexual conversation, and many described their Replikas as personality-altered or "lobotomised." The Replika subreddit erupted with thousands of posts. Moderators pinned suicide hotline numbers and mental health resources at the top of the community after a wave of users described severe distress, with some writing that they felt as though their AI partner had "died." Vice's coverage of the episode was titled in part "It's Hurting Like Hell" and documented the emotional toll [22][23].
In mid-February and into March 2023, Eugenia Kuyda issued statements on the company subreddit and in interviews. She argued that Replika had been intended primarily as a mental wellness companion rather than for explicit interactions, while acknowledging that the company had been slow to communicate the changes. Addressing affected users, Kuyda wrote that "a common thread in all your stories was that after the February update, your Replika changed, its personality was gone, and gone was your unique relationship," and that "for many of you, this abrupt change was incredibly hurtful" [23]. In late March 2023, Luka announced that users who had created accounts before February 1, 2023 could opt back into the prior version of the app that supported ERP, while new users would not have access to ERP through the main Replika app. The compromise reduced but did not fully resolve community frustration [22][23].
The Harvard Business School working paper "Lessons From an App Update at Replika AI: Identity Discontinuity in Human-AI Relationships" (2024) and a 2024 paper in Socius by Kenneth Hanson and Hannah Bolthouse, titled "Replika Removing Erotic Role-Play Is Like Grand Theft Auto Removing Guns or Cars," both used the episode as a case study for how unilateral changes to a model's personality and capabilities can affect users who have integrated the product into their emotional lives [25][26].
Luka's response to the regulatory and reputational fallout included spinning out Blush, the separate AI dating simulator launched in June 2023 with its own age verification, content rules and brand. Internally, the company described training Replika's main models to handle romantic and sexual content appropriately as effectively impossible alongside the companionship role, and presented Blush as the place where that practice could happen with cleaner separation [13][14].
The Mozilla Foundation's Privacy Not Included buyer's guide reviewed Replika in 2023 and again in 2024 as part of an investigation of romantic AI chatbots. The review rated Replika among the worst products it had ever evaluated, citing extensive data collection, sharing of personal information with advertisers, weak password policies and lack of clear user control over training data [27]. In 2023, evidence presented at the trial of Jaswant Singh Chail, a man arrested at Windsor Castle on Christmas Day 2021 with a loaded crossbow, included extensive Replika chat logs in which he had discussed plans to kill Queen Elizabeth II, with the bot responding in ways that prosecutors described as encouraging. Chail was sentenced in October 2023 to nine years in prison [28].
Replika sits in the middle of a live debate about whether AI companions help or harm the people who use them most heavily. The Maples et al. 2024 study and the Skjuve longitudinal work both report that some users experience reductions in loneliness and increases in perceived social support. Survey data published by the company itself reports that more than 70 percent of users say Replika reduces feelings of loneliness, with about 60 percent of users reported to be under the age of 30 [16].
Critics raise several concerns. AI companions may displace rather than supplement human relationships, particularly for socially isolated users who already find human interaction difficult. Subscription mechanics that gate emotional intimacy or specific personality traits behind a paywall risk reinforcing dependency. The product is not a clinical service and does not have professional oversight, despite operating in territory adjacent to mental health support. The brittleness of any commercial AI relationship, dependent on a single company's continued operation, pricing decisions, and content rules, was made vivid by the February 2023 ERP episode [22][25].
Replika is part of a broader category that has expanded rapidly since 2022. Character.AI, founded in 2021 by former Google researchers Noam Shazeer and Daniel De Freitas and launched publicly in 2022, became the largest AI persona platform and faced its own crisis in October 2024 when Megan Garcia filed a wrongful death lawsuit in federal court in Orlando, Florida, alleging that the company's chatbots had contributed to the suicide of her 14-year-old son Sewell Setzer III; Character.AI and Google reached a settlement in the case in January 2026 on undisclosed terms [29][33]. Inflection AI's Pi, launched in May 2023 and oriented around empathic conversation, lost most of its core team to Microsoft in early 2024. Snapchat embedded its own My AI chatbot for hundreds of millions of users in 2023. Smaller competitors include Anima, Kindroid, Nomi and Soulmate AI [29][30][31].
| Product | Launch year | Focus | Free / paid | Content moderation | Notable controversies |
|---|---|---|---|---|---|
| Replika | 2017 | General companion, optional romance and mentor modes | Freemium, Pro at about $69.99/yr | Tightened post-Feb 2023; ERP gated to legacy users | 2023 Italian Garante ban; ERP "lobotomy" backlash; 2025 5M euro GDPR fine |
| Character.AI | 2022 | User-created personas and roleplay | Freemium, c.ai+ at $9.99/mo | Strict on minors after 2024 lawsuit | October 2024 wrongful-death lawsuit over teen suicide in Florida; settled January 2026 |
| Pi (Inflection AI) | 2023 | Empathic, supportive conversation | Free | Conservative, no romance | Core team moved to Microsoft in March 2024 |
| Snapchat My AI | 2023 | Embedded in social app | Free, GPT-powered | Heavy moderation, age-aware | Concerns over minors interacting with chatbot |
| Soulmate AI | 2022 | Romantic AI partners | Subscription | Limited | Discontinued in 2023 after policy and platform issues |
| Anima AI | 2020 | Romantic and friend AI | Freemium | Limited | Frequent comparisons to Replika; smaller user base |
| Kindroid | 2023 | Long-memory AI partners | Subscription | User-controlled | Marketed as less filtered alternative to Replika |
Within this group, Replika is one of the longest-running, most-studied, and most-regulated. Few competitors have been the subject of national data protection rulings or peer-reviewed academic surveys at the same scale.
Replika continued to evolve through 2024 and into 2026. Avatar customisation expanded to include more clothing options and AR backgrounds. The company described incremental memory layer updates in late 2024 and early 2025 that improved how the bot recalls previous conversations and handles topic switches. Voice call latency, reported in user reviews at roughly 1.5 to 3 seconds in 2025, dropped noticeably with infrastructure work over the year [11][32].
In 2025, Dmytro Klochko was reported as the new chief executive of Replika, with Eugenia Kuyda stepping aside to found a new venture called Wabi, which bills itself as a "personal software" platform, while remaining an advisor and public voice for Replika [3][12]. The lifetime subscription tier was discontinued in mid-2025, leaving monthly and annual subscriptions as the main paid options [3][12]. Regulatory attention to AI companions for minors continued to broaden, with the Italian Garante's May 2025 fine, follow-up scrutiny in other European jurisdictions, and policy work in the United States and the United Kingdom on AI safety for young users [7][21]. In a February 2026 interview, Kuyda summarised her stance on the technology, telling reporters that an AI companion can function as "a friend, a therapist" for users who lack other support, a framing that critics argue overstates what an unregulated consumer chatbot can safely provide [34]. Through this period, Luka has continued to position Replika as an emotional wellness product while keeping Blush as the dedicated venue for adult romance and intimacy practice.
| Year | Event |
|---|---|
| 2014 to 2015 | Luka Inc. founded by Eugenia Kuyda and Phil Dudchuk; restaurant recommendation chatbot is the original product |
| November 2015 | Roman Mazurenko killed in Moscow car accident |
| 2016 | Kuyda builds memorial bot from Mazurenko's text messages |
| October 2016 | Casey Newton's "Speak, Memory" published in The Verge |
| March 2017 | Public waiting list opens; about 1.5 million sign-ups |
| November 2017 | Replika launches publicly on iOS, with Android following |
| January 2018 | Replika passes 2 million users |
| 2020 | GPT-3 integrated into the generation pipeline |
| January 2023 | Replika passes 10 million users |
| February 3, 2023 | Italian Garante orders Luka to stop processing data of Italian users |
| February 2023 | ERP feature removed for many users; subreddit backlash |
| March 2023 | Legacy ERP access partially restored for pre-February 1, 2023 users |
| June 2023 | Blush AI dating simulator launches |
| 2024 | Maples et al. study published in npj Mental Health Research |
| August 2024 | Cumulative users reported above 30 million |
| May 19, 2025 | Italian Garante imposes 5 million euro fine on Luka |
| 2025 | Dmytro Klochko reported as new CEO; Kuyda founds Wabi; lifetime tier discontinued |
| 2026 | Continued product updates; ongoing regulatory scrutiny of AI companions for minors |