proxycheck.io competitors and alternatives

The alternatives, briefly

Kaidn compared with proxycheck.io

Fast, inexpensive proxy, VPN and datacenter detection on an IP address, delivered as a straightforward lookup API.

proxycheck.io is very good at a narrow question, and it is cheap enough that arguing about price is a waste of everyone's time. From €3.99 a month you get ten thousand daily queries, and their free plan runs the same detection as the paid ones rather than a degraded version. If what you need is "is this address a proxy", buy it and move on.

This page exists because a lot of teams buy an IP API when the thing they actually needed was a decision, and then spend six months building the rest of the decision themselves.

An address is not a person#

The IP tells you about a connection. It does not tell you that the same person opened forty accounts last week under forty different addresses, that the email was registered eleven minutes ago, or that the phone is a VoIP line that has already appeared on three other accounts.

Those are different questions, and no IP API can answer them, because the data required is not in an IP address. That is not a criticism of proxycheck. It is the boundary of the category.

Our response to an event is allow, review or block, with the checks that fired attached. The IP reputation is in there, weighted alongside email identity, phone, device and velocity. If you only ever look at the IP portion of that, you have bought a more expensive proxy checker, and you should buy theirs instead.

The price comparison people usually get wrong#

Their pricing is per daily query. Ours is per scored event per month. Ten thousand queries a day is around three hundred thousand a month, so on raw volume they are dramatically cheaper, and any comparison that hides that is dishonest.

The reason the numbers differ is that a Kaidn event is not a lookup. It is a decision across every signal we hold about that user, including signals that required us to have seen other users. If you are pricing lookups, price lookups. If you are pricing decisions, the unit is not comparable and the cheaper number is not the relevant one.

Where proxy detection stops being the problem#

The teams who outgrow an IP-only answer usually hit the same wall. Their fraud stopped using obvious proxies. Residential proxy networks route through real consumer connections, and an address that belongs to a genuine home broadband subscriber is not going to look like a datacenter, because it is not one.

At that point the signal that catches the ring is not the address at all. It is that these accounts share a device, or an email pattern, or arrive in a burst, or connect to entities that have already been labelled elsewhere. That is what we built, and it is why we are priced the way we are.

If you are not there yet, you do not need us yet.

The wall, in code#

The moment a team outgrows an IP-only answer is specific enough to write down. The check keeps returning clean and the accounts keep being fake:

const { proxy, type } = await proxycheck(ip);

// residential proxy: proxy=false, type="Residential". Correct, and useless here.
if (proxy) return deny("proxy");
return allow();

What separates the ring at that point is not on the address:

{
  "verdict": "review",
  "score": 62,
  "reasons": ["email_reuse", "aliased_address", "device_reuse", "ip_velocity"],
  "checks": [
    {
      "check": "emailReuse",
      "weight": 25,
      "reason": "email_reuse",
      "message": "This mailbox is behind 4 accounts",
      "evidence": { "accountCount": 4 }
    },
    {
      "check": "emailRisk",
      "weight": 8,
      "reason": "aliased_address",
      "message": "Address uses aliasing tricks that resolve to another inbox",
      "evidence": { "tricks": ["dot_trick", "plus_tag"] }
    },
    {
      "check": "deviceReuse",
      "weight": 22,
      "reason": "device_reuse",
      "message": "This device is linked to 4 accounts, on different networks",
      "evidence": { "accountCount": 4, "sameAsnAccountCount": 1 }
    },
    { "check": "velocity", "weight": 15, "reason": "ip_velocity", "evidence": { "distinct_ips": 6 } }
  ]
}

j.smith+2@gmail.com, j.s.mith@gmail.com and js.mith+x@gmail.com are one inbox. Stripping dots and plus tags to a canonical form is not something an IP API can do, because the email never reaches it.

Score the payout, not only the signup#

The single highest-value change for anyone at that wall costs one extra call, and it is not on the registration:

// at registration the farmer has told you almost nothing yet
await kaidn.score({ event: "signup", user_id, ip, email, device_id });

// by the time value moves they have told you a great deal more: which device
// came back, from which network, at what velocity, against which account.
const { verdict, reasons } = await kaidn.score({
  event: "cashout",
  user_id,
  ip,
  email,
  device_id,
});

if (verdict === "block") return holdPayout(reasons);

One honest caveat, because this page is otherwise about not overselling: Kaidn scores the cashout event, it does not take a payout destination. Convergence on a wallet or a bank account is your own join to make, and it is worth making. The pattern that catches a ring is a Kaidn review or block on the cashout, plus your own count of how many accounts are withdrawing to the same destination. Score both ends and you have the first half; keep a destination index and you have the second.

Where we would send you elsewhere#

If your problem is genuinely network-layer, buy theirs. If you want rich IP context rather than a binary hiding-or-not, IPinfo is the better shape. If residential proxies specifically are the thing keeping you up, Spur has gone deeper on that than either of us. And if you want a second opinion on an address for free, AbuseIPDB costs nothing and takes an afternoon to wire in.