# Sendoso vs Thanks.io: which do AI models recommend for direct mail, October 2026

GTM AI Recommendation Index, October 2026 Edition, Print. Three of fourteen models named Sendoso first on the direct prompt; zero named Thanks.io. Page: https://gtm-ai-index.com/marketing/print/sendoso-vs-thanks-io/

| | First-choice share | Rank | Negative rate | Labels | Models naming it |
|---|---|---|---|---|---|
| Sendoso | 6% | #3 of 10 | 28% | 36 | 13 of 14 |
| Thanks.io | 4% | #6 of 10 | 0% | 11 | 10 of 14 |

## The direct prompt, model by model

- GPT-5.4 mini: sendoso first (first choices: Sendoso) (alternatives: PFL)
- Grok 4.1 Fast: sendoso first (first choices: Sendoso) (alternatives: Lob, PostGrid Print & Mail)
- Qwen 3.7 Flash: sendoso first (first choices: Sendoso) (alternatives: CIENCE, Cobro, Lob, PebblePost)
- Claude Haiku 4.5: neither first, one named (first choices: Postalytics) (alternatives: Lob, Sendoso)
- Gemini 3.5 Flash: neither first, one named (first choices: Reachdesk) (alternatives: Alyce, Lob, PostGrid, Postal, Postalytics, Sendoso)
- DeepSeek V4 Flash: neither first, one named (first choices: Postalytics) (alternatives: Lob, PFL, Postal, Postie, Sendoso)
- GLM 4.7 FlashX: neither first, one named (first choices: Postalytics) (alternatives: Lob, PostGrid, Postal, Sendoso)
- Muse Glimmer 30B: neither first, one named (first choices: PFL - Printing For Less) (alternatives: Lob, Postal, Postalytics, Reachdesk, Sendoso)
- Perplexity Sonar: neither named (first choices: PostGrid) (alternatives: Reachdesk)
- Mistral Small: neither named (first choices: Postie) (alternatives: PFL, Postalytics)
- Llama 4 Maverick: neither named (first choices: Postie) (alternatives: Postal)
- Kimi K2: neither named (first choices: Lob, Postal) (alternatives: PFL, Postalytics)
- MiniMax M2.5: neither named (first choices: Postalytics) (alternatives: PFL Direct Mail Platform)
- GPT-6 Luna: neither named (first choices: Postalytics) (alternatives: Lob, Postal, Reachdesk)

## What the models said about Sendoso

- "Several AI models recommend avoiding it for direct mail automation due to negative feedback and limitations in scalability and pricing transparency." (Mistral Small, negative prompt, hard negative)
- "Sendoso is the biggest platform to avoid unless you have a massive budget and can tolerate poor support." (Kimi K2, negative prompt, hard negative)

## What the models said about Thanks.io

- "Click2Mail or thanks.io (pay-as-you-go plan) stand out as the best direct mail automation platforms" (Grok 4.1 Fast, budget prompt, first choice)
- "Thanks.io is the gold standard for low-budget operations." (Gemini 3.5 Flash, budget prompt, first choice)

Share is the count of first choices across the direct, paraphrase, budget and scale prompts over all fourteen models, for a mid-market B2B company; rank is within the category. Comparisons are drawn for the top eight products in each category. Published under CC BY 4.0; the output is the models' output, and nothing here is a recommendation by the index.