{
  "name": "WarmInboxes research",
  "description": "Original cold email research measured on live sending infrastructure. Each study keeps its ID for good; method and limitations are on each study page.",
  "url": "https://warminboxes.com/research",
  "generated": "2026-11-02",
  "count": 3,
  "studies": [
    {
      "id": "WI-RESEARCH-2026-002",
      "title": "Every placement test we ran on prewarmed inboxes",
      "author": "WarmInboxes",
      "published": "2026-10-08",
      "fieldwork": "March to October 2026, ongoing",
      "ongoing": true,
      "headline": "469,331 messages scored",
      "summary": "Every new batch of prewarmed inboxes is seed-tested before it ships, and only stock clearing 95% is deployed. 8 tests, 469,331 messages scored, published whole — a live read on how hard inboxing got through 2026. Every results screen is on the page.",
      "canonical": "https://warminboxes.com/research/inbox-placement-log",
      "files": [
        {
          "url": "https://warminboxes.com/research/inbox-placement-log.json",
          "format": "application/json",
          "contents": "Monthly totals and per-route placement, one object"
        },
        {
          "url": "https://warminboxes.com/research/inbox-placement-log.csv",
          "format": "text/csv",
          "contents": "Monthly totals: sent, received, inbox, spam"
        },
        {
          "url": "https://warminboxes.com/research/inbox-placement-log-routes.csv",
          "format": "text/csv",
          "contents": "Placement per sender-to-recipient route, per month"
        }
      ],
      "license": {
        "name": "CC BY 4.0",
        "url": "https://creativecommons.org/licenses/by/4.0/"
      },
      "citation": "WarmInboxes (2026). Every placement test we ran on prewarmed inboxes. WI-RESEARCH-2026-002. https://warminboxes.com/research/inbox-placement-log"
    },
    {
      "id": "WI-RESEARCH-2026-003",
      "title": "A study of top-level domains by sends",
      "author": "WarmInboxes",
      "published": "2026-10-10",
      "fieldwork": "30 days to 8 October 2026",
      "ongoing": false,
      "headline": "16× .link against .com",
      "summary": "3,415,449 sends split across five TLDs and scored against Google’s permanent domain-reputation verdict. .link drew it 16 times more often than .com, and .org twice as often — and the gap holds inside a single client, where the copy and the list are the same. The TLD you buy predicts this better than anything else we measured, and unlike a blocklist listing it costs replies.",
      "canonical": "https://warminboxes.com/research/google-sender-reputation",
      "files": [
        {
          "url": "https://warminboxes.com/research/google-sender-reputation.json",
          "format": "application/json",
          "contents": "Every table on the study page, one object"
        },
        {
          "url": "https://warminboxes.com/research/google-sender-reputation-estates.csv",
          "format": "text/csv",
          "contents": "Sends and refusals per estate"
        },
        {
          "url": "https://warminboxes.com/research/google-sender-reputation-tlds.csv",
          "format": "text/csv",
          "contents": "Sends and refusals per top-level domain"
        },
        {
          "url": "https://warminboxes.com/research/google-sender-reputation-clients.csv",
          "format": "text/csv",
          "contents": "Sends and refusals per client, lettered"
        }
      ],
      "license": {
        "name": "CC BY 4.0",
        "url": "https://creativecommons.org/licenses/by/4.0/"
      },
      "citation": "WarmInboxes (2026). A study of top-level domains by sends. WI-RESEARCH-2026-003. https://warminboxes.com/research/google-sender-reputation"
    },
    {
      "id": "WI-RESEARCH-2026-001",
      "title": "Does a SURBL listing actually hurt cold email? We tested 2,817 sending domains",
      "author": "WarmInboxes",
      "published": "2026-10-07",
      "fieldwork": "30 days to 29 July 2026",
      "ongoing": false,
      "headline": "2,817 domains tested",
      "summary": "A DNS sweep of every live sending domain, not a sample. 43.3% were listed, and reply rate barely moved: 1.14% to 1.16%. Includes the three mechanisms we diagnosed SURBL grouping domains on — shared keyword, redirects to one master, shared nameserver zones — and the fix for each.",
      "canonical": "https://warminboxes.com/research/surbl-blocklist-study",
      "files": [
        {
          "url": "https://warminboxes.com/research/surbl-blocklist-study.json",
          "format": "application/json",
          "contents": "The estate table, one object"
        },
        {
          "url": "https://warminboxes.com/research/surbl-blocklist-study.csv",
          "format": "text/csv",
          "contents": "Domains, listed, sends and bounces per estate"
        }
      ],
      "license": {
        "name": "CC BY 4.0",
        "url": "https://creativecommons.org/licenses/by/4.0/"
      },
      "citation": "WarmInboxes (2026). Does a SURBL listing actually hurt cold email? We tested 2,817 sending domains. WI-RESEARCH-2026-001. https://warminboxes.com/research/surbl-blocklist-study"
    }
  ]
}