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> Use this file to discover available pages before exploring further.
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# Reverse IP lookup: find the contact behind an IP address

Give an IP address and get back the contact and household details linked to it, when a record exists. Use it to put a name to anonymous website traffic, or to fill in contact detail on an inbound lead.

## What it tells you

- Whether a record was matched at all, so you can tell a real hit from an empty result.
- The first and last name linked to the address.
- An email address for that contact.
- Location detail behind the address: city, region, country code and ZIP code.
- The credits the lookup used and your remaining balance.

## What you need to provide

One input: the IP address you want to resolve. Both IPv4 (the familiar four-number format) and IPv6 (the longer, newer format) are accepted.

## What it costs

10 credits per lookup. Live per-product costs are shown on the Billing page in your dashboard.

## How to run it

- In the dashboard: Reverse IP Lookup
- From your code: POST /v1/reverse-ip-append, then see the Developer Hub at app.1lookup.io/developer-hub.

## Good to know

- Not every IP address has a record behind it. Check the matched flag first, because an unmatched lookup still returns a response, just without contact detail.
- This returns personal data about identifiable people. Use it for legitimate business purposes only.
- Results are point-in-time. IP addresses are shared and reassigned, so the contact behind one can change after your lookup, and a match reflects what the data showed at the moment you ran it.
- One IP address can cover a whole household or office. Treat a match as the people associated with that connection, not proof of who was at the keyboard.
- This costs more per lookup than a standard IP lookup, so run it on the addresses you actually want contact data for rather than on all traffic.