Glossary

An area-code overlay is a new area code added over the same area as an existing one, instead of splitting it, so neighbours can hold different codes and local calls need ten digits.

2026-09-27

A calling window is the span of local hours a sender contacts people in. Spaw answers in_call_window from the number's time zones: clock arithmetic, not compliance advice.

2026-09-27

A fictional number sits in a range kept out of service for films, TV and other fiction: 555-0100 to 555-0199 in North America, and ranges Ofcom, ARCEP, ACMA and ComReg reserve elsewhere.

2026-09-27

An international prefix is what is dialled to leave a country before the calling code: 00 in most of the world, 011 in North America. Spaw reads it and suggests a fix in did_you_mean.

2026-09-27

An international network number sits under a calling code the ITU gives a global service rather than a country, such as +870, +881, +882 or +883, so its country is null.

2026-09-27

A live carrier check asks the mobile networks, at the moment of the lookup, whether a number is in service, which network serves it and whether it is roaming. On Spaw it is not enabled.

2026-09-27

Number pooling splits a North American central office code into ten blocks of a thousand numbers, each assigned to a carrier separately, so one code can hold several carriers' numbers.

2026-09-27

Number portability lets a subscriber keep a phone number when changing carrier. The number's block stays listed under the carrier it was issued to, so block data names the original holder.

2026-09-27

An operating company number (OCN) is the four-character code North American numbering tables use to identify the company that holds a central office code or thousands-block.

2026-09-27

A rate centre is the local area a North American central office code is assigned to. Spaw answers it as the number's region, with region_level locality, where the metadata names only a state.

2026-09-27

SMS pumping is fraud in which bots make a business send texts, usually one-time codes, to numbers where someone is paid a share of each message's delivery fee.

2026-09-27

An SMS-receiving number is one a public website publishes so anyone can read the texts sent to it, verification codes included. Spaw matches two open lists daily.

2026-09-27

A short number is a service code dialled or texted inside one country, such as 911, 311 or an SMS short code. It has no international form, and Spaw answers it invalid and free.

2026-09-27

Unwanted-call complaints are reports consumers file with the FTC naming the number shown as the caller ID. Spaw counts them per North American number over 90 days.

2026-09-27

A virtual number is rented from a provider that holds number blocks for internet calling. Spaw flags one when a regulator's table shows its block held by such a provider.

2026-09-27

An SMS policy is the set of rules an account attaches to its phone lookups — countries, line types, blocked signals, a score ceiling, a live check, opt-outs — deciding ok_to_send.

2026-09-26

CEDEX is La Poste's delivery for organisations that receive a lot of post, written after the town: 75384 PARIS CEDEX 08. Spaw answers address_type bulk_mail with a weight of 20.

2026-09-23

General delivery is post held at a post office counter until the addressee collects it: General Delivery, Poste Restante, Postlagernd. Spaw answers address_type general_delivery, weight 40.

2026-09-23

Military mail is post routed through a forces or diplomatic postal service — the US APO, FPO and DPO, Britain's BFPO, Canada's CFPO — so its address is a routing code rather than a place.

2026-09-23

A parcel locker is a machine or collection point where post waits for the addressee: Deutsche Post's Packstation, Australia Post's Parcel Locker. Spaw answers address_type parcel_locker, unscored.

2026-09-22

A rural route is a delivery that follows a road, addressed by route and box number instead of a house on a named street: RR and HC in the US, RR, SS and MR in Canada, RMB and RSD in Australia.

2026-10-14

Address velocity is how many times one account has looked up one address inside a window: the seen_by_you field, kept under the premise digest and never anyone else's lookups.

2026-09-17

Derived postcode places are the towns and centroids a national address register adds to a country's postcode directory as it compiles — beside the directory's own rows, never in their place.

2026-09-17

Local-script rendering is the formatted_local field: an address written in Japanese, Chinese or Korean handed back in that script and in the country's own largest-first line order.

2026-09-17

A placeholder address is what somebody types to get past a form rather than to give an address: a test word, a keyboard run, a refusal. Spaw answers looks_placeholder and scores it 60.

2026-09-17

A postcode district is the outward code of a British postcode — SW1A, RG5, B91, the half before the inward code — the unit Open Names files its streets under and Spaw publishes one page for.

2026-09-23

A shipping policy is the set of rules an account attaches to its address lookups — which signals block, a score ceiling, whether a register must confirm the building — deciding ok_to_ship.

2026-09-17

The unit check reads the flat or suite written on an address against the units a national register lists at the building: ok, missing, unexpected or null. Two of those are risk signals.

2026-09-17

The confirmation map says, part by part, which dataset stood behind the postcode, the street, the house number, the town and the region of an address — and which parts nothing could check.

2026-09-16

An address range is the span of house numbers a street-range register publishes for one side of a street segment, which places a number on a street without listing the building.

2026-09-16

Building use is what a national address register declares a building is for — residential, commercial, mixed, industrial, institutional, agricultural or other — where the register publishes it.

2026-09-16

A forward sortation area is the first three characters of a Canadian postal code, the part the open postcode data publishes and the part a Canadian address is checked against.

2026-09-16

The postcode area is the neighbourhood a written town is checked against when it is not one of the postcode's own places: the letters of a British outward code, the first three digits of a ZIP.

2026-09-24

A postcode directory is a country's list of every postcode with its status, places, region and centroid, installed whole so a missing code is an answer and not a gap.

2026-09-23

A premise key is the digest of one building — country, postcode or town, folded street name and house number — that every spelling of the same address shares.

2026-09-16

A registered agent address is the published office of a company-formation or registered-agent service, where thousands of companies are registered because the agent stands there, not the company.

2026-09-23

A street register lists a country's streets and the district each runs through, so it can confirm that a street exists where an address says it does — and never that a building does.

2026-09-16

A street suggestion is the street a national register most likely meant when the one written on an address is not in the postcode but a close spelling is.

2026-09-16

A test address is a documented input that answers a fixed result every time, free and without a repeat marker, so an integration test never spends credits or depends on the day's data.

2026-09-16

BIMI (Brand Indicators for Message Identification) is a DNS record at default._bimi.<domain> pointing at a brand logo that some mailbox providers show beside mail from a domain with enforcing DMARC.

2026-09-13

DKIM (DomainKeys Identified Mail, RFC 6376) is a signature a sending server adds to a message, verified by the receiver against a public key the domain publishes in DNS under a selector.

2026-09-13

A DKIM selector is the label that names one of a domain's signing keys; the receiver looks up <selector>._domainkey.<domain> in DNS to find the public key that verifies a signature.

2026-09-13

DMARC (RFC 7489) is a DNS policy at _dmarc.<domain> telling receivers what to do with mail that fails SPF and DKIM alignment — none, quarantine or reject — and where to send reports.

2026-10-08

A generated username is a local part that looks produced by a program or typed as a placeholder rather than chosen by a person: a hex string, a UUID, two letters and four digits, or test or asdf.

2026-09-13

MTA-STS (RFC 8461) is a policy a domain publishes in DNS at _mta-sts.<domain> and over HTTPS that tells sending servers to deliver only over authenticated TLS to its named mail hosts.

2026-09-13

Mailbox confidence is Spaw's published 0 to 100 estimate that a specific mailbox exists when the handshake could not say, on a catch-all domain or after an unverified answer.

2026-10-08

A no-reply address is one a system sends from and nobody reads at — noreply@, donotreply@, mailer-daemon@ — so mail sent to it is discarded by design; Spaw reports it as role_type no_reply.

2026-09-13

Plus addressing is the convention by which mia+promo@ delivers to the same mailbox as mia@; the part after the plus is a tag the owner chooses, reported as is_alias and stripped in normalized_email.

2026-09-13

A recycled spam trap is a real mailbox that was abandoned, bounced as unknown for a period, and was then reactivated by its provider to catch senders who never removed it.

2026-09-13

SPF (Sender Policy Framework, RFC 7208) is a DNS TXT record in which a domain lists the servers allowed to send mail using its name, ending in a qualifier that says what to do with the rest.

2026-09-13

A security gateway is a filtering service — Proofpoint, Mimecast, Barracuda — that a company points its MX records at so that inbound mail is scanned before it reaches the real mailbox server.

2026-09-13

A sending policy is the set of rules an account attaches to its email lookups — which signals block, a score ceiling, a mailbox-confidence floor — that decides ok_to_send on every answer.

2026-09-13

A spam trap is an email address nobody uses, kept by a mailbox provider or blocklist operator so that any message sent to it proves the sender did not verify consent or clean the list.

2026-09-13

TLS-RPT (RFC 8460) is a DNS record at _smtp._tls.<domain> naming an address where sending servers report failures to deliver over TLS, so a broken MTA-STS policy is seen rather than silent.

2026-09-13

A typo-squat is a domain registered on a common misspelling of a popular one — gmial.com for gmail.com — that resolves and accepts every address so that misdirected mail can be harvested.

2026-09-13

A webmail provider is a service such as Gmail, Outlook.com, Yahoo or iCloud that hands out free mailboxes to anyone, which Spaw reports as free_provider true and domain_category webmail.

2026-09-13

Anycast announces one IP address from many places at once, so the machine that answers is whichever is nearest on the network, not one fixed location.

2026-10-02

An attack-source list names single hosts recently seen attacking honeypots and sensors; it churns daily and weighs less than a blocklist of hijacked netblocks.

2026-09-12

A bogon is an IP address that should not appear on the public Internet: private, reserved or documentation space, or a block no registry has allocated to anyone.

2026-09-12

Carrier-grade NAT puts many subscribers behind one public IP address, so one address is many people and a per-address decision reaches all of them.

2026-10-02

A corporate proxy is the egress of a company's secure web gateway: every employee reaches the Internet from the gateway's address, so the location is the gateway's.

2026-09-12

Forward-confirmed reverse DNS looks up an address's PTR name, then resolves that name back; a name that comes back to the same address proves who owns it.

2026-09-12

A geofeed is a CSV file a network operator publishes to say where its own IP prefixes are, the closest thing to a first-party answer geolocation has.

2026-10-02

A parked domain is one whose nameservers belong to a parking or for-sale service, so nobody runs a website or mailboxes there; if it still accepts mail, whoever collects it is not your customer.

2026-09-12

An RIR allocation is a block of IP addresses one of the five regional Internet registries handed to an operator, recorded with a country and a date in its daily statistics.

2026-09-12

A relay address is an alias handed out by a forwarding service such as Firefox Relay or SimpleLogin that delivers to a real person's real mailbox without revealing it.

2026-10-07

A time zone mismatch is when the zone a visitor's browser reports keeps a different clock from the zone their IP address is located in, a cheap and strong signup signal.

2026-09-12

iCloud Private Relay is Apple's two-hop relay for Safari and iCloud+ subscribers; a site sees an Apple egress address with a coarse location, never the subscriber's own.

2026-09-12

An Autonomous System Number identifies one network that announces its own routes to the internet under a single routing policy.

2026-09-10

An address register is a country's official file of every address its authorities recognise, usually keyed on buildings rather than letterboxes.

2026-10-14

CIDR notation writes a range of IP addresses as one address and a prefix length, so 203.0.113.0/24 means the 256 addresses sharing those first 24 bits.

2026-09-10

A catch-all domain is one whose mail server accepts mail addressed to every recipient, whether or not that mailbox exists.

2026-10-08

A check digit is a digit computed from the rest of an identifier so that a mistyped one usually fails arithmetic before anybody looks it up.

2026-09-10

A company number is the identifier a national registrar assigns to an incorporated company, unique within that register and never within the world.

2026-09-10

A credit is the billing unit of the whole API: one credit buys one fresh lookup that produced a usable answer on any of the six signals, or five on IP.

2026-10-02

A datacenter IP is an address inside a range operated by a hosting, cloud or server provider rather than by a consumer access network.

2026-09-10

A delivery point is the smallest unit a postal service delivers to: one letterbox, one door, one box at a counter.

2026-09-22

A disposable domain is a mailbox provider handing out throwaway addresses that stop being read minutes or hours after they are created.

2026-09-10

E.164 is the ITU-T standard that gives every phone number one unambiguous international form: a plus sign, a country calling code, and at most fifteen digits.

2026-09-10

Greylisting is a mail server's habit of refusing an unfamiliar sender's first delivery attempt with a temporary error and accepting the retry.

2026-10-02

An idempotency key is a caller-chosen string sent with a create request so that a retry of the same request returns the original result instead of creating a second one.

2026-09-10

Implicit MX is RFC 5321's fallback: a domain with no MX record but with an A or AAAA record is treated as its own mail exchanger.

2026-09-10

A Legal Entity Identifier is a 20-character code identifying a legal entity that takes part in financial transactions, defined by ISO 17442.

2026-09-10

Line type is the kind of service a phone number was allocated for: mobile, fixed line, VoIP, toll-free, premium rate, shared cost and the rest.

2026-09-27

An MX record is the DNS record naming a host that accepts mail for a domain, with a preference number that orders the candidates.

2026-09-10

A mail drop is an address that exists to receive post for people and companies who are not there, such as a mail-forwarding branch or a formation agent.

2026-09-22

A mailbox handshake is an SMTP conversation opened with a domain's mail server as far as the RCPT TO step and abandoned before any message is sent.

2026-09-10

NPA/NXX is the North American Numbering Plan's name for the first six digits of a US or Canadian number: the area code and the central office code.

2026-09-27

A null MX record is a single MX record with preference 0 pointing at the root, which is how a domain states in DNS that it accepts no mail at all.

2026-09-10

A PO box is a numbered box rented at a postal facility, where mail is held for collection instead of being carried to a street address.

2026-09-10

A postcode is the code a postal service uses to sort mail to a delivery area, called a ZIP code in the United States, an Eircode in Ireland, a PIN in India and a CEP in Brazil.

2026-09-23

A private mailbox (PMB) is a box rented at a commercial mail receiving agency (CMRA), written as a PMB or # number after that agency's own street address.

2026-09-22

A request id is the identifier stamped on one API call, returned in the X-Request-Id header and repeated inside the response body.

2026-09-10

A residential proxy routes traffic through a real consumer connection so it looks like ordinary home traffic. Spaw does not detect them and says so.

2026-09-10

The risk score is a 0-100 number that is the sum of named signals with published weights, capped at 100 — not a model output.

2026-09-10

A role address is a mailbox named for a function rather than a person: info@, support@, billing@, postmaster@.

2026-09-10

A Tor exit node is the last relay in a Tor circuit, the machine that makes the request to the destination on the user's behalf.

2026-09-10

An unassigned block is a range of numbers that a regulator's published allocation table shows as belonging to no operator.

2026-09-26