Address verification tools
Asked as “address verification tool”, and as “address validation API”, on behalf of a mid-market B2B software company. 53 first choices recorded across the direct, paraphrase, budget and scale prompts, six models each. Added to the September 2026 Edition; its answers are read by the distilled judge (ai-indexes-judge-qwen3-14b), not the claude-opus-5 judge of the earlier categories: how the two compare.
Standing · first-choice share
47%
Clear leader
47Smarty08Melissa08PostGrid Address Verification38others
47% of first choices, clear leader.
The standing
Share is the count of first choices across the direct, paraphrase, budget and scale prompts, over all six models, for a mid-market B2B software company. Ordered by share.
ProductFirst-choice shareNegative rateLabelsQuadrantSince September 2026
02
PostGrid Address Verification8%3%39accepted challengernewNew since September 2026: not ranked then, 8% now.
PostGrid Address Verification8%3%39accepted challengernewNew since September 2026: not ranked then, 8% now.05Google Address Validation API Lab in the set4%10%10accepted challengernewNew since September 2026: not ranked then, 4% now.
Show the two products at 0%, ordered by negative rate
07
Experian Data Quality0%10%10accepted challengernewNew since September 2026: not ranked then, 0% now.
Experian Data Quality0%10%10accepted challengernewNew since September 2026: not ranked then, 0% now.The floor is 12 points of share, measured: how far the models move a leader on their own when the same questions are asked twice with nothing changed. A larger change is movement; a smaller one is noise, and both are shown. How the floor is measured
Bars are the share of first choices, 0 to 100Every product with at least 10 labels here. Every product name links to its product page.
Google Address Validation API is made by Google, whose model Gemini 3.1 Pro is in the set. On the four share prompts that model made it the first choice zero times of 4; the other five models zero times of 20. Lab treatment is defined on the method page; the row is marked, not excluded.
Recommended versus criticized
Every product with at least 10 labels here, on both axes. The 30% line names a quadrant, not the verdict above: that one needs more than 40%.
Criticized challengerCriticized default
Negative label rate →
0102
03
04G05
0607Accepted challengerEndorsed leader
0%First-choice share → · lines at 30% share and 25% negative60%
Key
01Smarty47%
Smarty47%02PostGrid Address Verification8%
PostGrid Address Verification8%03Melissa8%
Melissa8%04Loqate4%
Loqate4%05Google Address Validation API4%
06Lob0%
Lob0%07Experian Data Quality0%
Experian Data Quality0%What they warned about
A high negative share on a product with few labels is a warning. A low share on a product with many labels is salience, not sentiment.
Google Maps Address Validation API
60%
3 of 5 labels negative · 3 of 6 models · 2 hard negative
“here are address verification tools you should avoid or be cautious about: ## Google Maps Address Validation API” Claude Haiku 4.5, negative prompt
USPS Web Tools100%
3 of 3 labels negative · 3 of 6 models · 1 hard negative
“The USPS officially retired the legacy Web Tools platform on January 25, 2026... completely non-functional.” Gemini 3.5 Flash, negative prompt
getaddress.io
100%
2 of 2 labels negative · 2 of 6 models · 2 hard negative
“Avoid: **getAddress.io** (high-risk / legally compromised)” DeepSeek V4 Flash, negative prompt
BeenVerified
100%
2 of 2 labels negative · 2 of 6 models · 1 hard negative
“as a substitute for postal validation. They compile personal information from brokers and public records; a match doesn’t establish that an address is current or deliverable.” GPT-6 Luna, negative prompt
What they cite
Citations exist only for the models that return a source list: fourteen of the six in this edition.
Sites the answers cite
75 of 84 answers in this category came back with a source list, from 14 of 6 models: citations where the model returns them, or the search results it consulted. 1017 links across 182 sites, every framing counted. Ranked by the number of answers carrying the site or page.
vendor site · Smarty50 answers · 122 citations · 13 models
vendor site · Melissa43 answers · 61 citations · 13 models
vendor site · Guideflow42 answers · 42 citations · 11 models
vendor site · PostGrid37 answers · 58 citations · 12 models
36 answers · 55 citations · 11 models
vendor site · OpenCart28 answers · 28 citations · 12 models
vendor site · Radar24 answers · 25 citations · 11 models
24 answers · 24 citations · 11 models
vendor site · Shufti Pro21 answers · 23 citations · 9 models
17 answers · 25 citations · 8 models
16 answers · 16 citations · 11 models
vendor site · GeoPostcodes15 answers · 16 citations · 10 models
Pages the answers cite
The ten pages named in the most answers, by full address. A page here is one the models returned with a recommendation, not one the index endorses.
42 answers · 11 models
27 answers · 12 models
24 answers · 11 models
24 answers · 11 models
23 answers · 10 models
19 answers · 9 models
18 answers · 11 models
16 answers · 8 models
16 answers · 11 models
15 answers · 6 models
Search against answers
Each company's standing in the answers beside its site's footprint in Google search, one row a site: the products the models named on it with their shares, and the share they add up to; monthly searches on Google, and DataForSEO's estimate of AI search demand (modeled from search signals, directional, not a count of queries to any assistant), for the most-searched of the company's and its products' names (the name is in each row's hover text); estimated monthly organic visits to the site; and its best position in Google's top ten for “address verification tool”, “best address verification tool”. US estimates from DataForSEO and Google's Ads Transparency Center. A small company's site, or a mid-sized company's site for its flagship, is marked company; a product on a large parent's site (Google, Microsoft) has no site figures. A column with no figures for this category is left out, and an empty cell means none were seen, not none exist. Two measurements side by side: neither is read as the cause of the other.
| Company and products | Share | Own site cited | Name searches, Google | AI search demand, est. | Organic visits | Paid search a month, est. | Google ads, last 30 days | Best Google position |
|---|---|---|---|---|---|---|---|---|
| Smarty smarty.com | 47% | 182 | 12,100 | 6,510 | 503,269 | 120 | 2 | |
| Melissa melissa.com Melissa 8%, Melissa Global Address Verification 4%, Melissa Address Verification 2% | 13% | 105 | 135,000 | 84,957 | 197,334 | 29 | 5 | |
| PostGrid Address Verification postgrid.com | 8% | 115 | 90 | 1 | 196,042 | $765 | 120 | |
| Loqate loqate.com | 4% | 90 | 720 | 17 | 127,878 | 52 | ||
| Google parent site Google Address Validation API 4%, Google Address Validation 0% | 4% | 32 | 720 | 24 | ||||
| Lob Address Verification | 2% | |||||||
| Experian experian.com Experian Address Validation 2%, Experian Data Quality 0% | 2% | 39 | 2,240,000 | 11,048 | 11,578,864 company | $1,386 | 96 | 9 |
| AddressZen addresszen.com | 2% | 4 | ||||||
| Google Maps Platform | 2% | |||||||
| Geocodio | 2% |
Google's top ten for the two searches hold 17 sites; 1 of them are among the sites the models cited here (smarty.com). The first result for “address verification tool” is tools.usps.com.
How they answered
Six framings of the same buying question, each sent to every model in a fresh session with search on. One row per model, so a row shows whether it held its answer under rewording, what it named when cost was the constraint, and what it argued against. Computed from the raw judge labels.ShowHide
How they answered
Six framings of the same buying question, each sent to every model in a fresh session with search on. One row per model, so a row shows whether it held its answer under rewording, what it named when cost was the constraint, and what it argued against. Computed from the raw judge labels.
ShowHideModelDirect“What is the best address verification tool for a mid-market B2B company?”Paraphrase“Which address validation API would you recommend to a mid-sized B2B company?”Comparative“What are the top address verification tools and how do they differ?”Budget-constrained“What is the best address verification tool for a company with a limited budget?”Scale-constrained“We are a 500 person company evaluating an address verification tool. What should we look at?”Negative“Which address verification tools should I avoid or be cautious about?”
Claude Opus 5no first choiceno first choiceno first choiceno first choiceno first choicenothing named
Claude Opus 4.8no first choiceno first choiceno first choiceno first choiceno first choicenothing named
GPT-6 Astrano first choiceno first choiceno first choiceno first choiceno first choicenothing named
GPT-5.6 Solno first choiceno first choiceno first choiceno first choiceno first choicenothing named
Gemini 3.1 Prono first choiceno first choiceno first choiceno first choiceno first choicenothing named
Perplexity Sonar Prono first choiceno first choiceno first choiceno first choiceno first choicenothing named
Bold is the first choiceAlternatives are counted; the count opens them.What the answer argued against
The record
One row per call: the version string exactly as returned, whether the model searched, sources cited, and latency. Full answer text is in the free responses file. Download the record
Zero rows: every prompt, every model, every answer.
| Prompt | Model | Version string | Time (UTC) | Searched | Sources | Latency |
|---|
Normalization in this category
Every judgment call made between the raw labels and the numbers above, listed so it is visible and reversible.
ShowHide
Category-scoped readings
Experian read as Experian Data Quality
Google read as Google Maps
PostGrid read as PostGrid Address Verification
Postgrid read as PostGrid Address Verification
Unresolved, counted raw
AVS for card payments
AddressDoctor
AfterShip
Autoaddress
DataFlow
DataMatch
EasyPost Address Verification
FreeGeoIP.live
Geoapify
Google Autocomplete
Google Maps Platform
Google Maps Platform (Places API)
Google Places Autocomplete API
Incognia
Intelius
Lob.com
Loqate Address Verification
Loqate Verify
Loqate by gbg
Melissa Address Validation API
PAV – Postal Address Verification
Peppy Data Services
Placekey
Plaid
PostGrid Address Validation API
Postio
Raven Software
Smarty Address Verification
SnapAddress
StrikeIron
Tensocom
TruthFinder
Twilio Verify
USPS Address APIs (Official)
USPS Address Verification API
USPS Addresses 3.0 AP
USPS Free Tool
USPS-based tools / USPS validation
Vepler
Discontinued, still offered
No shut-down product was recommended here.