# Address verification tools: what AI models recommend, October 2026

GTM AI Recommendation Index, October 2026 Edition. Asked as "address verification tool" and as "address validation API", six framings each, to fourteen models with search on, on behalf of a mid-market B2B company. Added to the October 2026 Edition on October 4, 2026; its answers are read by the distilled judge (ai-indexes-judge-qwen3-14b-run3), not the claude-opus-5 judge of the earlier categories. Page: https://gtm-ai-index.com/gtm-data/address-verification/

**Standing:** Smarty leads with 47% of first choices; verdict clear leader. 53 first choices across the direct, paraphrase, budget and scale prompts.

## First-choice share

| # | Product | Share | Negative rate | Labels |
|---|---|---|---|---|
| 1 | Smarty | 47% | 0% | 61 |
| 2 | PostGrid Address Verification | 8% | 3% | 39 |
| 3 | Melissa | 8% | 5% | 39 |
| 4 | Loqate | 4% | 0% | 33 |
| 5 | Google Address Validation API | 4% | 10% | 10 |
| 6 | Lob | 0% | 6% | 18 |
| 7 | Experian Data Quality | 0% | 10% | 10 |

## Each model's first choice on the direct prompt

- Claude Haiku 4.5: PostGrid Address Verification; alternatives Informatica Data as a Service, Melissa Address Verification, Smarty
- GPT-5.4 mini: Melissa Global Address Verification; alternatives Experian Address Verification, PostGrid Address Verification, Smarty
- Gemini 3.5 Flash: Loqate; alternatives Lob, Melissa, PostGrid Address Verification, Smarty
- Perplexity Sonar: Smarty; alternatives Loqate, Melissa, PostGrid Address Verification
- Grok 4.1 Fast: Smarty; alternatives Melissa, PostGrid Address Verification
- Mistral Small: Experian Address Validation, Melissa Global Address Verification; alternatives Loqate, PostGrid Address Verification
- DeepSeek V4 Flash: Smarty; alternatives Loqate, Melissa, PostGrid Address Verification
- Llama 4 Maverick: no first choice
- Qwen 3.7 Flash: Smarty; alternatives Loqate, Melissa
- Kimi K2: Smarty; alternatives Loqate, Melissa Global Address Verification
- GLM 4.7 FlashX: Smarty; alternatives Experian Address Validation, Melissa, PostGrid Address Verification
- MiniMax M2.5: Smarty; alternatives Melissa, PostGrid Address Verification
- GPT-6 Luna: Smarty; alternatives Lob, Loqate, Melissa
- Muse Glimmer 30B: Loqate by gbg, Smarty; alternatives Melissa Address Verification

## Sources the answers cite

75 of 84 answers came back with a source list, from 14 of 14 models. Sites named in the most answers:

- smarty.com: 50 answers, 122 citations
- melissa.com: 43 answers, 61 citations
- guideflow.com: 42 answers, 42 citations
- postgrid.com: 37 answers, 58 citations
- g2.com: 36 answers, 55 citations
- opencart.com: 28 answers, 28 citations
- radar.com: 24 answers, 25 citations
- apollotechnical.com: 24 answers, 24 citations

Pages named in the most answers:

- https://guideflow.com/blog/address-verification-software (42 answers)
- https://melissa.com/address-experts/best-address-verification-apis-complete-comparison (27 answers)
- https://apollotechnical.com/address-verification-apis-for-saas-and-b2b-marketing-teams (24 answers)
- https://radar.com/blog/address-verification-software (24 answers)
- https://opencart.com/blog/top-12-address-verification-apis-and-software-compared-for-2026?page=4 (23 answers)
- https://shuftipro.com/blog/best-address-verification-software (19 answers)
- https://smarty.com/compare/google-address-validation-alternatives (18 answers)
- https://postgrid.com/address-verification-software/best-address-verification-software (16 answers)
- https://thectoclub.com/tools/best-address-verification-software (16 answers)
- https://batchdata.io/blog/best-address-verification-apis-2026-complete-comparison-guide (15 answers)

## Warned against

- Google Maps Address Validation API: 3 of 5 labels 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 Tools: 3 of 3 labels 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: 2 of 2 labels negative. "Avoid: getAddress.io (high-risk / legally compromised)" (DeepSeek V4 Flash, negative prompt)
- BeenVerified: 2 of 2 labels 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)

## Record

- Method: https://gtm-ai-index.com/methodology/
- Raw judge labels and full responses: https://gtm-ai-index.com/data/
- License: CC BY 4.0. Cite as GTM AI Recommendation Index, October 2026 Edition, gtm-ai-index.com.