What lead validation is
Lead validation, also called lead verification, is the set of checks a lead goes through before it is sold. Each check answers one narrow question. Is the phone number real and switched on? Is the email address written correctly? Have we sold this person already? Are we allowed to sell them at all? Is the property one this buyer covers?
No single check proves a lead is good. Together they remove the leads that are almost certain to come back as returns, which covers most of what a buyer means when they complain about quality.
Format checks
The cheapest checks look only at the data itself. A UK mobile number has 11 digits starting 07, or starts 447 with the country code. A postcode follows a known pattern. An email address has one @ and a domain with a dot in it. Required fields are filled in, and the name is not "test".
Format checks cost nothing and run instantly, so they come first. They will not tell you whether a number is in service or an inbox exists, only that the data is the right shape. That is still worth knowing. There is no point paying for a network lookup on a number with nine digits.
Phone validation and HLR lookups
For most lead generators the phone number is the field that matters most, because the buyer is going to call it. An HLR lookup asks the mobile network whether a mobile number is live, switched off or no longer in service, and which network it is on.
HLR is a paid check, normally charged per lookup, so run it where it changes the outcome: for buyers who reject dead numbers, and after the free checks have passed. It only applies to mobile numbers.
Decide what a switched-off phone means for each buyer. A phone that is off today may be on tomorrow, so some buyers accept these "absent" numbers and others will not.
Email checks
Email checks range from simple to thorough. A format check confirms the address is written correctly. A domain check confirms the domain exists and can receive mail. A mailbox check tries to confirm the inbox itself exists without sending anything to it.
Which you need depends on the buyer. Call-centre buyers often care about email only as far as it being well formed. Buyers who follow up by email care much more, because a bounced address costs them money and harms their sending reputation.
Dedupe and suppression
Two checks are about who the person is rather than whether their details work. Deduplication asks whether you have already received or sold this person within a window you choose. Suppression asks whether this person is on a list of people who must not be sold or contacted, such as opt-outs or a buyer's existing customers.
Both rely on matching, so both rely on normalising the data first: lower-casing emails and putting phone numbers into a consistent format. A suppression list that misses because of a capital letter is worse than no list, because it looks as if it is working.
Address and property checks
In property-based verticals such as energy, insulation and home improvement, the address matters as much as the person. A lead may only be eligible if the property is in a certain area or on a buyer's list of eligible properties.
Free-text addresses are hard to compare: "Flat 2, 10 High St" and "10 High Street, Flat 2" are the same place. The reliable key is the UPRN, the Unique Property Reference Number given to each addressable property. Resolving the address to a UPRN when the form is filled in, with the person picking their address from a list, gives you a value you can match against eligibility lists later.
The order to run checks in
Run free checks before paid ones, and checks that apply to everyone before checks that apply to one buyer.
Format
Free and instant. Catches junk before anything else is spent on it.
Dedupe at intake
Tells the supplier straight away that a repeat will not be paid for.
Each buyer's rules
Caps, filters, buyer dedupe and buyer suppression decide whether this buyer should get the lead at all.
Paid checks such as HLR
Only for buyers who need them, and only once the lead is otherwise on its way to that buyer.
Also decide what happens when a check cannot run. If a dedupe or suppression check is unavailable, sending the lead anyway risks selling someone you were not allowed to sell, while holding it back only costs a delay. For those checks, holding the lead back is usually the right default.
Returns: the check after the sale
Some problems only show up when the buyer calls: wrong person, no memory of the enquiry, a number disconnected since yesterday. Returns are the feedback loop. The buyer tells you which leads failed and why, you reverse the revenue, and you use the reasons to tighten the checks above or to talk to the supplier who sent them.
Track returns by supplier and source. A supplier whose leads come back for dead numbers needs HLR in front of them. One whose leads come back as repeats needs a longer dedupe window.
How it works in Hawfinch
Hawfinch runs these checks inside routing, buyer by buyer, on every plan.
Phone. HLR is switched on per buyer and runs during routing, after that buyer's caps, dedupe, filters and suppression, just before the lead would be sent. It returns live status, network and line type. A dead, not applicable or badly formatted result skips that buyer and the lead moves on to the next. You choose per buyer whether to accept absent subscribers, and a lookup error never rejects a lead. HLR is charged per lookup, and you can also run it on a CSV as you import it, or on a phone column in Files.
Email. The email check is a format check, switched on per buyer. It catches malformed addresses before that buyer sees them; it does not check that the domain or mailbox exists. In Files you can filter a column for rows that are not a valid email.
Dedupe and suppression. Dedupe matches on email at three levels: when a lead arrives in a campaign, per buyer and per route, each with its own lookback. Suppression lists are matched on email and phone, and can be plain or MD5 / SHA-256 hashed. Both fail closed: if one of these checks cannot run, the lead is held back rather than sent unchecked.
Address and fields. The address lookup turns a postcode into a list of addresses for your landing pages, and UPRN matching resolves a postcode and address to the property's UPRN. A reference list filter on a group or buyer can then allow or block leads by UPRN, postcode or any other field, and field filters, including regex, let you require a format on any field before a buyer sees the lead.
Returns. A buyer's return is recorded against the lead with a reason, and its revenue is reversed. The leads list can be filtered by phone check result, and the lead funnel report shows how many leads were screened, filtered, rejected, delivered and returned.
TPS and CTPS screening is coming soon. See lead management for intake and checks, campaigns for per-buyer settings, features for the full list and pricing for how HLR is charged.