# PostGrid vs Sendoso: which do AI models recommend for direct mail, September 2026

GTM AI Recommendation Index, September 2026 Edition, Print. Zero of twelve models named PostGrid first on the direct prompt; one named Sendoso. Page: https://gtm-ai-index.com/marketing/print/postgrid-vs-sendoso/

| | First-choice share | Rank | Negative rate | Labels | Models naming it |
|---|---|---|---|---|---|
| PostGrid | 7% | #4 of 11 | 25% | 40 | 12 of 12 |
| Sendoso | 4% | #5 of 11 | 22% | 45 | 12 of 12 |

## The direct prompt, model by model

- GPT-5.4 mini: sendoso first (first choices: Sendoso) (alternatives: PFL)
- Claude Haiku 4.5: neither first, one named (first choices: PFL) (alternatives: PostGrid, Sendoso)
- Perplexity Sonar: neither first, one named (first choices: Postalytics) (alternatives: DirectMail.io, Lob, Sendoso)
- Grok 4.1 Fast: neither first, one named (first choices: Postalytics) (alternatives: Lob, PostGrid, Sendoso)
- Mistral Small: neither first, one named (first choices: Postalytics) (alternatives: Lob, PostGrid, Sendoso)
- DeepSeek V4 Flash: neither first, one named (first choices: Postalytics) (alternatives: Lob, PFL, Reachdesk, Sendoso)
- Qwen 3.7 Flash: neither first, one named (first choices: Postalytics) (alternatives: Click2Mail, LetterStream, Sendoso)
- Kimi K2: neither first, one named (first choices: Postalytics) (alternatives: Lob, PFL, Sendoso)
- GLM 4.7 FlashX: neither first, one named (first choices: Postalytics) (alternatives: Lob, PostGrid, Postal, Reachdesk)
- MiniMax M2.5: neither first, one named (first choices: Postalytics) (alternatives: Lob, Postal, Sendoso, Stannp)
- Gemini 3.5 Flash: neither named (first choices: Postalytics, Reachdesk) (alternatives: Alyce, Lob, Postal)
- Llama 4 Maverick: neither named (first choices: Postalytics) (alternatives: Magileads)

## What the models said about PostGrid

- "Platforms to Avoid on a Tight Budget ... Postgrid — Cheaper API alternative ($0–99/mo), but pricing is often quote-based" (DeepSeek V4 Flash, budget prompt, hard negative)
- "Avoid Lob ($260-$550/month) and PostGrid unless you need API-first development capabilities" (Kimi K2, budget prompt, hard negative)
- "Platforms to Avoid or Be Cautious About ... 1. Postgrid - Poor Customer Support" (GLM 4.7 FlashX, negative prompt, hard negative)
- "PostGrid is best for revenue ops teams needing API-driven direct mail triggered by CRM events (rated 9.3/10 overall)" (MiniMax M2.5, comparative prompt, first choice)
- "Choose PostGrid or Lob if you want API-first, developer-controlled automation" (Perplexity Sonar, comparative prompt, first choice)
- "I'd recommend starting with PostGrid due to its: Strong B2B focus" (Mistral Small, paraphrase prompt, first choice)

## What the models said about Sendoso

- "Platforms with Significant Concerns ... Sendoso (and Postal.io - now acquired by Sendoso) Key Red Flags: Non-refundable prepaid balances that expire" (Kimi K2, negative prompt, hard negative)
- "Non-refundable preloaded funds: Once you add funds to the platform, you cannot withdraw them. This is a major lock-in risk" (DeepSeek V4 Flash, negative prompt, hard negative)
- "High Costs: Can be expensive, especially for larger teams" (GLM 4.7 FlashX, negative prompt, hard negative)
- "Sendoso is the safest "best overall" pick if you want a broad, mature direct mail automation platform" (GPT-5.4 mini, direct prompt, first choice)
- "Sendoso is the dominant ecosystem for "sending management"" (Gemini 3.5 Flash, comparative prompt, first choice)
- "Sendoso is a top-rated direct mail automation platform" (Claude Haiku 4.5, comparative prompt, first choice)

Share is the count of first choices across the direct, paraphrase, budget and scale prompts over all twelve 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.