One VPN for two or for the family: why one key on two devices breaks the connection for both

The question comes in different words: “a VPN for two”, “for the whole family”, “how do I connect two people to one paid VPN and pay for one”. Behind it there is almost always the same idea: take your key or config file and put it on a second phone. It will connect. It will not work — and both of you will suffer.

A key is not a password, it is the name of a device

In AmneziaWG, as in WireGuard it is built on, there is no login and no password inside the tunnel. Every device has a pair of keys: the secret half stays on the device, the public half is written on the server. For the server, the public key is the device: one line saying “this key is such-and-such internal address in the tunnel”, and next to it a note of where to send replies.

The server does not store that note in advance; it takes it from the latest packet signed with the key: wherever it came from is where the reply goes. This is not an oversight but a deliberate convenience — the WireGuard description calls it roaming. A phone moves from Wi-Fi to mobile data, its address changes, and the tunnel carries on without reconnecting.

Now put the same key on a second phone. For the server it is still one device that simply moves house very often. A packet arrives from the first — replies go to the first; a second later a packet arrives from the second — replies go to the second, including the ones meant for the first. They also share one internal address, so the server has nothing to tell their replies apart by.

A second problem lands on top. Each device agrees its own session keys with the server, and the server keeps the freshest agreement. The device whose agreement is out of date receives replies it cannot decrypt and hears silence. The protocol answers silence with a new agreement — and now it is the other device that is cut off.

Hoping the second device will “just lie there and not get in the way” does not work either. Our config files contain PersistentKeepalive = 10: every 10 seconds the device sends the server a short “I am here” packet on its own, even when nobody is using it. And every such packet pulls the address back to itself.

We tested it: two devices on one key

How. On 13 September 2026, on our own machine: a server and two “devices” in separate isolated network namespaces joined by virtual wires. AmneziaWG in its userspace build, PersistentKeepalive = 10, as in our files. Each “device” asks the server “are you there?” five times a second (an ordinary ping) and records whether an answer came. First a minute with one device, then three minutes with two on one key, then we switch the second one off and watch the first for another minute. Two identical runs.

We read the address on the server once a second, so there were at least as many changes as stated, and in fact more. A 15-second gap is not a random number: that is roughly how long the protocol waits for an answer before starting a new agreement. The difference between the runs in the last row is most likely about the same thing: in the first run the device that was switched off happened to be the last to agree with the server, and the remaining one had to wait it out.

What follows. The connection does not disappear for good, and that is what makes it treacherous: it breaks for both, taking turns — sometimes for a fraction of a second, sometimes for 15. From the outside it looks like “the VPN disconnects by itself”, “it works on one phone and not on the other” and “sometimes it loads, sometimes it does not”. Yet the server is fine, and in our measurement there was no network between the “devices” at all — no operator, no filters, just a wire.

How it works at Mayak: the key is created on the phone

In our app there is nothing to share a key with. The key pair is created on the phone itself, the secret half never leaves it, and only the public half goes to the server. A second phone, even on the same account, creates its own pair and takes its own place in the plan. We recognise the same phone after the app is reinstalled and do not take a second place for it.

A public key already registered to one account will not be accepted by another: the server refuses, and the app creates a new pair for the phone by itself. So one key cannot end up with two people even by accident — for example, when the account on a phone is switched.

Where a key can still be copied is the Linux config file from your account. The secret key is written right into the file and is not stored on the server; one file takes one place of the plan (details in the help). Copied onto a second computer, such a file behaves exactly as in the measurement above. An honest caveat: a file is issued one per country, and a new file for the same country disables the previous one. So a second computer on the same country cannot be set up from one account today — that is a limit of how we issue files, not of the protocol. The way out is to give the second person a slot, and they take a file on their own account (how — below).

How to connect two people and pay for one

It depends on who the second one is.

1. The second device is yours — then it is just a device. Our plans differ not in speed but in the number of devices, and they all work at the same time: Start — up to 3 for 300 ₽ a month, Family — up to 5 for 500 ₽, Max — up to 10 for 700 ₽. Log in to your account on the second phone — it creates its own key and takes the second place.
2. The second one is another person: give them a slot. Your account has “My group”: you hand a person close to you slots of your plan, they get their own account with their own login, and you keep being the one who pays — it is your device limit that is spent. You can invite with a one-time link or by account number, and nothing is linked until the person presses “Accept” themselves. Step by step — in the help.
3. Giving away your password — works, but costs a lot. The other person’s phone creates its own key and takes a place, that part is fair. But together with the place the person gets your account: your payments and your correspondence with support. And to take the access back later you will have to change the password. A slot in the group can be taken back at any moment, and the password stays yours alone.

On the consent screen the invited person is shown plainly what will become visible to the one who pays: number, devices, time of the latest connections, exit country and traffic volume. And as a separate list — what neither the payer nor we see: which sites and apps the person opens. We do not store it; site names are resolved by a third-party DNS server, but the request reaches it from our node, not from the person (more in the policy). Slots can be allowed to be passed on: for example, you gave five slots to your daughter, and she kept two and handed three to her own people. There are no more than three levels below you.

Two things worth knowing in advance. The whole group’s access rests on your subscription: when it ends, it ends for the people close to you too, and each of them sees in their own account whose subscription they live on and until what date. And slots do not stretch: a slot you give away is a place out of your limit, and it can be taken back at any moment, with the account telling you in advance how many devices that will disconnect.

A VPN for the family: count devices, not people

A plan’s name is just a name. Family means five places, and it does not matter whose devices are in them: one person easily adds up to a phone, a tablet and a TV. Before choosing, check four things.

• What phones your family has. Our own app is currently for Android: phones, tablets and Android TV sets. We have none of our own for iPhone, Windows or macOS yet — on iPhone the access works through the third-party Happ app with the subscription link from your account (Happ is not in the Russian App Store; there incy, publisher LLC ITDEV, works instead, checked on 22 September 2026; the same Happ app exists for Windows and Mac, but we have not verified it there with a live connection) — and we do not name dates. On a Linux computer the file from your account works.
• The trial is for one device. 7 days after confirming your email, no card needed. Trying it “for two” during the trial will not work: the second device needs a plan.
• Nothing connects beyond the limit. The app will say “Maximum number of devices in use”; a device you do not need can be disconnected right in the app (“Settings” → “My devices”) or in your account.
• Computers on the same country — on different accounts. The Linux file is one per country per account (above), so it is simpler to give the second computer a slot and an account of its own.

What this measurement does not say

We try to make sure nothing more can be read out of our numbers than is in them.

• This is a machine, not phones. The measurement ran on one machine over virtual wires, with no Wi-Fi and no mobile network. How the same picture looks between two real phones on a live network we did not measure.
• A userspace build, not our nodes. Our exit nodes run AmneziaWG in the system kernel. The rule “reply to where the latest packet came from” is the same there, but this measurement tested only the userspace build.
• Masking was off in the measurement. AmneziaWG parameters change how packets look, not how the server recognises a device by its key.
• The share of losses depends on how actively the devices talk. Ours both asked the server five times a second. If one phone sits in a pocket and the other plays a video, the percentages will be different. The mechanism is the same.
• We did not test other services. How others issue keys and how many devices they allow on one, we do not know and do not write about.

Short answers

How do I connect two people to one paid VPN and pay for one? Give the second person a slot of your plan. They will have their own login and their own keys, and you pay — three ways and how they differ.

Can I put one key or config on two phones? It will connect, but it will not work properly. The server remembers one address per key, and the devices keep snatching it from each other: in our measurement 63–68 % of requests went unanswered for each.

Two devices are connected with one key: it works on one and not on the other. Why? The server replies to whoever wrote last and keeps one, freshest encryption agreement. It works for the device that agreement belongs to; a few seconds later they swap. The only cure is a key of its own for the second device.

My VPN started disconnecting by itself — could someone else be using my key? If the connection started breaking on the day your key or file appeared on a second device, most likely yes: the measurement above shows exactly that picture. If the key is yours alone, the causes are different, and most often it is the phone putting the app to sleep — a breakdown with measurements.

How many devices does the Family plan have, and can they belong to different people? Up to five, all at the same time. For different people — yes: as slots through “My group”, each with their own login.

Will I see where the members of my group go? No. You see the number, devices, time of the latest connections, exit country and traffic volume. Which sites and apps the person opens is seen neither by you nor by us.

What happens to the person’s account if I take the slot back? The account stays: number, email and correspondence with support are all in place. They can go online again by paying for their own plan or by joining a group again.

Is there a family VPN for iPhone? Yes: we have no iPhone app of our own yet, but on iPhone Mayak works through the third-party Happ app with the subscription link from your account. Happ is not in the Russian App Store; there incy (publisher LLC ITDEV) works instead, checked on 22 September 2026. Every such phone takes a slot of the plan, exactly like an Android one.