Private AI Assistants Compared: Lumo, Lorka AI and the Big Three on Price and Privacy

People now paste payslips, tenancy agreements and medical letters into chatbots without a second thought. We have reviewed two AI tools that take very different approaches, one built around privacy and one around choice, and set them against ChatGPT, Claude and Gemini on what they cost and what happens to your words.

Our Top AI Tool Picks at a Glance

• Best for privacy: Lumo, Proton’s assistant, with encrypted chat history, no logs and no training on your chats.
• Best free option: Lumo, usable without an account, with saved, encrypted history on a free Proton login.
• Best value paid plan: Lumo Plus, US$9.99 a month on annual billing, half the yearly cost of ChatGPT Plus or Claude Pro paid monthly.
• Best for using several models: Lorka AI, ChatGPT, Claude, Gemini and more behind one login and one bill.

The Best AI Tools, Ranked

AI Assistants Compared: Lumo and Lorka Against ChatGPT, Claude and Gemini

Prices are each company’s official US dollar figures for a monthly plan unless stated, before any local tax.

	Lumo	Lorka AI	ChatGPT	Claude	Gemini
Our rating	3.8	3.4	Not rated	Not rated	Not rated
Made by	Proton AG (Switzerland)	Palatine Global Capital LLC (US), aggregator	OpenAI (US)	Anthropic (US)	Google (US)
Free option	Yes, no account needed	Limited onboarding quota	Yes	Yes	Yes
Main paid plan	Lumo Plus, US$12.99 (£9.75 / €11.57), or US$9.99 (£7.50 / €8.90) on annual billing	Standard, US$29.99 (£22.50 / €26.71)	Plus, US$20 (£15.01 / €17.81)	Pro, US$20 (£15.01 / €17.81), or US$17 (£12.76 / €15.14) billed annually	Google AI Pro, US$19.99 (£15.00 / €17.80); Google AI Plus, US$4.99 (£3.74 / €4.44)
Top tier	None above Plus	Max, US$39.99 (£30.01 / €35.62)	Pro	Max, from US$100 (£75.04 / €89.06)	Google AI Ultra, from US$99.99 (£75.03 / €89.05)
Models	Open-source	Many providers	OpenAI’s own	Anthropic’s own	Google’s own
Zero-access encrypted history	Yes	No	No	No	No
Training on your chats	Never, Proton says	Not stated in its privacy policy	Opt-out available	Set out in Anthropic’s policies	Opt-out available

What Makes an AI Assistant Private? Encryption, Logs and Training

Three questions separate a private assistant from an ordinary one: who can read your conversations, how long they are kept, and whether they are used to train future models.

Lumo answers all three in the user’s favour. Proton says chats are encrypted in transit, saved history uses zero-access encryption so Proton cannot read it, Lumo keeps no logs whether or not Ghost mode is on, and conversations are never used for training or advertising. Ghost mode goes a step further and deletes a conversation when you close it.

The mainstream assistants have narrowed the gap. ChatGPT and Gemini let you opt out of training and turn off chat history. What they do not offer is encryption that locks the provider itself out, which is the one thing Lumo adds. There is a trade-off on transparency too: Proton names “open-source models” without listing which on its main pages, so you are trusting its description of the stack.

An aggregator adds a further step. To answer you, Lorka must pass your prompt to whichever company built the model you picked, and its privacy policy does not say how prompts are shared with those providers, how long conversations are kept or whether they may be used for training. It lists service providers including Google, Stripe, Firebase and Amplitude, and says some data may leave the European Economic Area under standard contractual clauses. For a recipe or a holiday plan, that may not matter. For a client file, it should.

Free AI Chatbots: How Far the No-Cost Tiers Go

ChatGPT, Claude, Gemini and Lumo all have free tiers, and for occasional use they are often enough.

Lumo’s is the least demanding to start: you can type a question at lumo.proton.me without creating an account. A free Proton account then adds encrypted, saved history and more messages, along with Proton Mail, Drive, Pass and VPN under the same login. The free tier includes web search, small file uploads, limited image generation, limited use of the most capable “Max” model and one Project. Proton does not publish exact message caps, and reviewers have found them tight for heavy daily use.

Lorka has no free plan in the usual sense. A free account gives a limited onboarding quota to explore the models and tools, and that quota matters more than usual, because its refund policy is far stricter than the “30-day guarantee” headline suggests. Use the quota properly before you pay.

AI Subscription Prices Compared: What a Year Really Costs

On monthly billing, the mainstream paid plans cluster at about US$20: ChatGPT Plus and Claude Pro at US$20, Google AI Pro at US$19.99. Google also sells a cheaper AI Plus tier at US$4.99 a month. Claude Pro falls to US$17 a month when you pay US$200 (£150.08 / €178.12) for the year up front. Lumo Plus is US$12.99 a month, or US$9.99 on annual billing. Lorka’s Standard plan, at US$29.99, costs half as much again as any single assistant’s main plan.

Worked example: a solicitor’s assistant in Leeds

She wants an AI helper for tidying letters and summarising long PDFs, and does not want client details in anyone’s training data.

• Lumo Plus, annual: US$119.88 (£89.96 / €106.77) a year.
• Lumo Plus, monthly: US$155.88 (£116.97 / €138.83), so annual billing saves US$36 (£27.01 / €32.06).
• ChatGPT Plus or Claude Pro, monthly: US$240 (£180.10 / €213.74) a year each, twice the annual Lumo bill.
• Claude Pro, annual: US$200 (£150.08 / €178.12), still US$80.12 (£60.12 / €71.35) more than annual Lumo Plus.
• Google AI Pro, monthly: US$239.88 (£180.01 / €213.64) a year.

For letters and summaries, Lumo is capable, and its privacy is the reason she is buying. For long analytical reports or complex coding, the dearer rivals are stronger, and some readers will keep one of them for that work and use Lumo for anything personal.

One Subscription, Many Models: When an AI Aggregator Makes Sense

Lorka’s pitch is that subscribing to seven services separately would cost US$142.98 (£107.29 / €127.34) a month. Few people pay for seven. The fairer test is the reader who pays for two.

Worked example: a copywriter in Lisbon

She uses ChatGPT for brainstorming and Claude for long editing jobs, paying US$20 a month for each: US$40 (£30.02 / €35.62) in all. Lorka Standard, at US$29.99 a month, saves her US$10.01 (£7.51 / €8.91) a month, or US$120.12 (£90.14 / €106.98) over a year of monthly billing, and adds Gemini, Grok and others.

If she pays for Claude annually instead, her two subscriptions come to US$37 a month, and Lorka’s saving shrinks to US$7.01 (£5.26 / €6.24) a month. For someone who only uses ChatGPT, Lorka costs US$9.99 (£7.50 / €8.90) a month more than ChatGPT Plus. The saving exists only if you would otherwise pay for more than one assistant.

Read the refund terms before you commit to a year. You must ask within 30 days and have used fewer than 20 messages, 5 images or 1 video in the billing cycle, and even then refunds are described as “exceptional, not guaranteed”. Cancel at least 72 hours before renewal, from Settings, then Manage subscription. Lorka publishes no hard message limits either, so if you plan heavy daily use, ask support for them in writing first.

Using AI With Sensitive Documents: A Sensible Routine

No assistant is a safe place for everything, but some habits make any of them safer.

1. Check the rules first. Many employers restrict which AI tools staff may use. Proton sells Lumo for Business at US$11.99 (£9.00 / €10.68) per user a month, billed annually, for firms that want a sanctioned option.
2. Strip what the task does not need. A summary of a tenancy agreement does not need the account number or a tenant’s date of birth.
3. Use a private session for one-off questions. Lumo’s Ghost mode deletes the conversation when you close it, which suits a medical question you will not revisit.
4. Group repeat work. Lumo’s Projects and Custom Lumos let a freelancer keep a Project per client and a house style set up once.
5. Check the sources. Switch on web search when you need current facts, and read the citations rather than trusting the summary.
6. Mind the connection. On café or hotel Wi-Fi, a VPN protects the connection itself, whichever assistant you use.

For documents that need to live somewhere private between AI sessions, Lumo can pull files straight from Proton Drive, which encrypts them on your device. Our security hub covers encrypted email and storage in more depth.

Where Your Chats Live: Jurisdiction and Hosting

Proton is a Swiss company, and Lumo is built and hosted in Europe on servers Proton controls. In August 2025 its chief executive, Andy Yen, said proposed changes to Swiss surveillance rules had led Proton to host Lumo’s servers in Germany, the first Proton product to move infrastructure out of Switzerland. Proton says Lumo still operates under Swiss legal protections.

Lorka is run by Palatine Global Capital LLC of Jacksonville, Florida, which is also the data controller under its privacy policy. Spanish operations are run by Always B-Focused, S.L. in Barcelona, disputes fall under Spanish law, and payments may pass through companies in Miami or Barcelona. None of this is unusual for a small software business, but it is more layers than you get from OpenAI, Anthropic or Google directly. There is no named data protection officer; privacy requests go to info@lorka.ai.

Mistral’s Le Chat, from Paris, is the closest European rival to Lumo, though it does not offer zero-access encryption.

How We Test and Score Each Tool

Every tool ranked here has a full review, scored on the same weighted criteria:

• Privacy and data handling (30%): encryption, logging, training policy, hosting and who the operator is.
• Price and value (25%): monthly and annual prices, what each plan includes and how it compares with buying direct.
• Capability (20%): how well it handles everyday jobs such as drafting, summarising and research, drawing on independent testing.
• Free tier and refunds (15%): what you can do without paying, and how easy it is to get your money back.
• Support and transparency (10%): published limits, support channels and what users say.

We check prices against each company’s own pricing page and convert US dollars into sterling and euros. ChatGPT, Claude and Gemini appear for comparison and are not ranked.

AI Assistant Questions Answered

Which AI chatbot is the most private?

Of the assistants here, Lumo. Proton says chat history is encrypted so Proton cannot read it, no logs are kept and conversations are never used for training.

Does ChatGPT train on my conversations?

ChatGPT lets you opt out of training and turn off chat history, as does Gemini. Neither offers encryption that keeps the provider out of your saved chats.

Is there an AI chatbot I can use without an account?

Yes. Lumo works at lumo.proton.me without signing up. A free Proton account adds saved, encrypted history and more messages.

Is Lumo better than ChatGPT?

For privacy, yes. For capability on complex, analytical tasks, ChatGPT and Claude are ahead.

What is the cheapest AI subscription?

Of the main plans compared here, Google AI Plus at US$4.99 (£3.74 / €4.44) a month is the lowest price. Among privacy-first options, Lumo Plus costs US$9.99 (£7.50 / €8.90) a month on annual billing.

How much do ChatGPT Plus, Claude Pro and Google AI Pro cost?

ChatGPT Plus and Claude Pro are US$20 (£15.01 / €17.81) a month, and Google AI Pro is US$19.99 (£15.00 / €17.80). Claude Pro drops to US$17 a month on annual billing. Local tax may be added.

Is Lorka AI legit?

Yes. It is a working paid service run by Palatine Global Capital LLC in Florida, with a 4.4 Trustpilot score from 339 reviews. It is not affiliated with OpenAI, Anthropic or Google.

Is Lorka AI cheaper than paying for ChatGPT and Claude separately?

If you pay monthly for both, yes: US$29.99 against US$40 a month. If you only use one assistant, buying it direct is cheaper.

Can I get a refund from Lorka AI?

Only within 30 days and only if you have used fewer than 20 messages, 5 images or 1 video in the billing cycle, and even then at Lorka’s discretion.

Is it safe to put work documents into an AI assistant?

Check your employer’s rules first and remove details the task does not need. Lumo’s encryption and no-logs policy make it one of the more private options, and Proton sells a business version.

Where is Lumo hosted?

In Europe, on Proton-controlled servers. Proton’s chief executive has said those servers are in Germany.

Is Lumo Plus included in Proton Unlimited?

No. Unlimited, Duo and Family include Lumo Free. Lumo Plus is included only in Proton Visionary.

Is there a Lumo or Lorka AI promo code?

Neither needs a Promo Code. Lumo Plus is 23% cheaper on annual billing, and Lorka advertises up to 67% off on annual plans; check the yearly total at checkout.