The short answer
3CX is a phone system that has grown an AI receptionist. Remi is an AI receptionist that happens to answer a phone. Almost everything else in this comparison follows from that.
If what you need is calls picked up, understood and routed to the right extension on a bill that does not move when the phones get busy, 3CX does that job and its pricing model is genuinely one of the more sensible ones in this market. If what you need is the call to end with an appointment in the diary, a deposit taken, a reminder queued and an overdue invoice chased, 3CX publishes none of that, and its own FAQ caps every AI call at three minutes.
Everything below comes from what each vendor publishes. The 3CX figures were checked on 24 August 2026 and are a snapshot only. Licence pricing changes, so confirm the current numbers with 3CX or your reseller before you commit to anything.
What the 3CX AI Receptionist actually is
3CX is a business phone system, a PBX, which you can self-host or run on 3CX's own hosted service. It has a large installed base among UK small businesses and the IT resellers who look after them. The AI Receptionist is a feature of that phone system rather than a product you can buy on its own, which is why it has no separate price.
In use, the AI sits at the front of your existing 3CX call flow. It answers, works out in plain language what the caller is asking for instead of making them press 1 for reception, answers questions from information you have loaded, and puts the call through to the right extension, queue or mailbox. It replaces the touch-tone menu, and it replaces it well.
What it does not appear to do is finish a booking. No calendar integration is named among the tools 3CX lists for the AI receptionist. There is no published appointment booking, no reminder sending, no deposit collection and no invoice chasing. If you want a call to end with a row written into a diary, that is not what this feature was built for, and 3CX does not claim otherwise.
What 3CX costs, and what sits outside that cost
There is no separate price for the AI Receptionist. It is bundled into the 3CX AI edition annual system licence, so you buy the licence and the feature comes with it. As published on 24 August 2026, the entry tier of that licence covers 8 simultaneous calls and is listed at $575 per year on the US site and €550 per year on the euro site. 3CX does not publish a verified GBP figure, so we are not going to convert one for you. Get the pound price in writing before you budget.
Two things about that licence are worth understanding, because they are unusual in this category.
It is sized by simultaneous calls, not by users or minutes. Eight calls at once is generous for a single-site clinic, and most practices will never touch the ceiling. That is a fair way to price a phone system.
The AI itself is not included. 3CX requires you to bring your own paid OpenAI account. The model usage behind every AI call is billed to you by OpenAI directly, separately from the 3CX licence, and it is uncapped except by whatever spending budget you set inside your own OpenAI account. So the honest description of the 3CX cost is a flat, predictable licence plus a variable AI bill that you own, monitor and cap yourself.
None of that is hidden and none of it is a trick. But it does mean the licence figure is not the whole cost, and it means somebody at your practice has to keep an eye on an OpenAI dashboard. If nobody does, an unusually busy month goes straight to your card. For comparison, Remi's lineup starts at £89 a month ex VAT with 500 talk-minutes included, with Standard at £149 for 1,000 talk-minutes, and 15p a minute above the included pool on either. The model costs sit inside that.
The three-minute cap is the real constraint
This is the detail that decides whether 3CX can do the job you are hiring for. 3CX's own FAQ states a hard three-minute limit on every AI call. When the AI reaches three minutes, the call has to go somewhere else: a person, a queue or voicemail.
Now set that against how long a real call takes. Practice-management data puts the average inbound call at three to five minutes, with roughly thirty seconds of handling around it. And a booking is not one question. It is a greeting, a reason for the visit, a clinician preference, a look at the diary, two or three slots offered, a name, a date of birth, a phone number, and a confirmation read back. Patients pause. They go and find their own calendar. They change their mind about the Tuesday.
Three minutes is comfortably enough to answer "what time do you close" or "are you taking new patients". It is not reliably enough to finish a booking. And a booking that runs out of time at minute three is worse than one that never started, because you have spent the caller's patience and somebody still has to ring them back.
Remi publishes no per-call time limit. Minutes come out of a monthly pool, 500 on the £89 Lite plan or 1,000 on the £149 Standard plan, and anything above that is 15p a minute. A four-minute call that ends in a booked appointment costs about 60p of overage at worst, and it does not get cut off mid-sentence.
Side by side
Both columns are what each vendor publishes, checked 24 August 2026. "Not published" means exactly that: we found no published capability, not that we know it is absent.
| Capability | Remi | 3CX AI Receptionist |
|---|---|---|
| Published price | From £89/month ex VAT (Lite, 500 min); £149 (Standard, 1,000 min) | No separate price. Bundled into the AI edition annual licence, entry tier $575/yr (US) or €550/yr (EUR) for 8 simultaneous calls. No GBP published |
| AI usage cost | Included: 500 talk-minutes on Lite, 1,000 on Standard, then 15p/min | Not included: your own paid OpenAI account, billed by OpenAI, uncapped except by the budget you set |
| Limit per call | None published | Hard 3-minute cap on every AI call |
| Books into a diary | Google Calendar, Acuity, Cliniko | No calendar integration named |
| WhatsApp booking and messaging | Yes, native | Not published |
| No-show reminders | Yes | Not published |
| Deposits at booking, no-show fees | Yes | Not published |
| Chases unpaid invoices | Yes | Not published |
| Win-backs, cancellation backfill, review chasing | Yes | Not published |
| Warm transfer to a human | Yes | Yes, and routing is its core strength |
| Setup | Done for you | Self-serve, or through a 3CX partner |
| Cost at high call volume | Rises above the plan's included minutes | Licence stays flat. OpenAI usage does not |
The maths, with the assumptions showing
Remi's formula is public: Lite is £89 + 15p for every minute above 500, Standard is £149 + 15p for every minute above 1,000, both ex VAT. Below is the cheaper of the two at four realistic volumes, assuming a 22-day working month and three-minute average calls. Change the assumptions and the numbers change with them, which is the point of showing them.
| Scenario | Talk-minutes/month | Remi |
|---|---|---|
| Sole practitioner, 8 calls/day at 2.5 min | 440 | £89 (Lite) |
| Small clinic, 20 calls/day | 1,320 | £197 (Standard) |
| Solo GP practice, 50 calls/day | 3,300 | £494 (Standard) |
| Four-partner practice, 200 calls/day | 13,200 | £1,979 (Standard) |
We are not going to put a matching 3CX column next to that, because we would have to invent most of it. 3CX publishes no GBP licence price, and the OpenAI half of the bill depends entirely on your call volume, your model choice and your own account. Anyone who shows you a precise pound-for-pound 3CX total has guessed at least half of it.
What can be said honestly is the shape of the two curves. The 3CX licence is flat: 13,200 minutes a month costs the same licence fee as 1,320 does, as long as you stay inside eight simultaneous calls. Remi's line rises, because above the included pool it is a per-minute service. At the bottom of that table the licence is a fraction of £89 a month. At the top, Remi is £1,979 and the 3CX licence has not moved at all.
So on licence cost alone, at volume, 3CX wins, and it is not close. The real question is what the difference buys: a call greeted and routed inside three minutes, or a call that ends with the appointment booked, the deposit taken, the reminder queued and the outstanding invoice chased. Our wider breakdown of what an AI receptionist costs in the UK runs the same maths against the per-minute vendors, most of which are far less kind at volume than 3CX is.
Where 3CX is the better choice
Said properly, not as a throat-clear before claiming we win anyway.
- You want a predictable bill at volume. This is the best argument for 3CX and it is a genuine one. A flat annual licence with no per-minute overage means a busy month costs the same as a quiet one. Most of this market, Remi included, charges for minutes above an allowance. 3CX does not. The caveat is that the flat part is the licence, and the OpenAI usage behind it is not flat.
- You already run 3CX. If your phones are on it, the AI receptionist is a switch inside a system your staff and your IT support already understand. That is a much smaller change than onboarding a new supplier, and it should weigh heavily.
- You want to own the phone system. 3CX can be self-hosted on your own infrastructure. If your practice has a policy about where systems run, or an IT partner who wants control of the PBX, that is a real requirement Remi does not answer. Remi is not a phone system.
- Your problem is routing, not booking. A multi-department site with a lot of extensions, where the pain is getting callers to the right person rather than into the diary, is exactly what this was built for. In that setting a three-minute cap is not a constraint at all.
- You want your own model relationship. Your OpenAI account, your keys, your budget and your own agreement with OpenAI.
How to choose between them
Three questions settle this in about ten minutes.
- What do you want the call to end with? If the answer is "in the right person's ear", 3CX is a good buy. If it is "in the diary, with a deposit taken and a reminder scheduled", the three-minute cap and the absence of a named calendar integration rule it out before price enters the conversation.
- How long are your calls really? Pull last month's log from your current phone system and find the median. If most calls are short enquiries, the cap will rarely bite. If your calls are bookings running four minutes and up, it will bite every single day.
- Who is going to watch the OpenAI bill? Somebody has to own that account, set the budget and check it. In a practice where the manager is already doing four jobs, an uncapped second bill is a real operational cost even when the pounds are modest.
Remi starts at £89 a month ex VAT with 500 talk-minutes included, and Standard is £149 for 1,000, with 15p a minute above whichever pool you are on. There is a one-week free trial, no setup fee, and you can cancel at any time.
It answers calls and WhatsApp, books into Google Calendar, Acuity and Cliniko, sends no-show reminders, takes deposits, applies no-show fees, chases unpaid invoices, backfills cancellations and asks happy patients for reviews. It is AI, not a team of people, and it hands the caller to a human whenever one is needed. You can see how it is set up for UK clinics, or read how the whole category compares with a traditional answering service and what it looks like inside a GP surgery.