{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "name": "WarmInboxes free deliverability tools",
  "description": "Every free tool on warminboxes.com. No signup, no key. Tools with an \"api\" field can be called directly as JSON over HTTP; tools with an \"mcp\" field are also exposed as MCP tools at /mcp.",
  "url": "https://warminboxes.com/deliverability-tools",
  "openapi": "https://warminboxes.com/openapi.json",
  "mcp": "https://warminboxes.com/mcp",
  "app": {
    "description": "These tools are free and read-only. Ordering and managing inboxes and domains is a separate authenticated API with its own documentation.",
    "api": "https://api.warminboxes.com/v1",
    "docs": "https://docs.warminboxes.com",
    "llms": "https://docs.warminboxes.com/llms.txt",
    "cli": "wib, downloadable from https://docs.warminboxes.com"
  },
  "generated": "2026-09-26",
  "count": 33,
  "tools": [
    {
      "name": "Cold Email AI",
      "url": "https://warminboxes.com/AI",
      "category": "Writing",
      "description": "Cold email copy from an assistant trained on real deliverability data",
      "api": null,
      "mcp": null
    },
    {
      "name": "Pre-Send Checker",
      "url": "https://warminboxes.com/pre-send-checker",
      "category": "Campaign QA",
      "description": "Upload a lead CSV + paste a sequence; audits merge tags against real CSV columns, list quality, spintax, links/formatting, and simulates send volume with follow-up accumulation",
      "api": null,
      "mcp": null
    },
    {
      "name": "Suppression Checker",
      "url": "https://warminboxes.com/suppression-checker",
      "category": "Campaign QA",
      "description": "Check a campaign list against customers/unsubscribes/bounces by exact email AND company domain; detects account collisions",
      "api": null,
      "mcp": null
    },
    {
      "name": "Spam Checker",
      "url": "https://warminboxes.com/spam-checker",
      "category": "Campaign QA",
      "description": "200+ weighted spam triggers and formatting red flags",
      "api": null,
      "mcp": null
    },
    {
      "name": "Inbox Previewer",
      "url": "https://warminboxes.com/inbox-previewer",
      "category": "Campaign QA",
      "description": "Sender/subject/snippet as Gmail and Outlook render them",
      "api": null,
      "mcp": null
    },
    {
      "name": "Spintax & Liquid Tester",
      "url": "https://warminboxes.com/spintax-tester",
      "category": "Campaign QA",
      "description": "Preview every spintax variation and personalization variable",
      "api": null,
      "mcp": null
    },
    {
      "name": "Bounce Analyzer",
      "url": "https://warminboxes.com/bounce-analyzer",
      "category": "Diagnostics",
      "description": "Paste NDRs/SMTP codes for plain-English root cause plus a pause-or-continue calculator",
      "api": null,
      "mcp": null
    },
    {
      "name": "Outlook SCL Analyzer",
      "url": "https://warminboxes.com/scl-analyzer",
      "category": "Diagnostics",
      "description": "Paste Microsoft 365 headers; explains SCL, BCL, SFV, composite auth, and why the message went to Junk",
      "api": null,
      "mcp": null
    },
    {
      "name": "Header Analyzer",
      "url": "https://warminboxes.com/header-analyzer",
      "category": "Diagnostics",
      "description": "SPF/DKIM/DMARC, alignment, and hops from raw headers",
      "api": null,
      "mcp": null
    },
    {
      "name": "Deliverability Checker",
      "url": "https://warminboxes.com/deliverability-checker",
      "category": "Diagnostics",
      "description": "A-F domain grade across SPF, DKIM, DMARC, MX, blacklists, domain age",
      "api": {
        "endpoint": "/.netlify/functions/check-deliverability",
        "params": [
          "domain"
        ]
      },
      "mcp": "check_deliverability"
    },
    {
      "name": "Blacklist Checker",
      "url": "https://warminboxes.com/blacklist-checker",
      "category": "Diagnostics",
      "description": "Domain/IP against 20+ blacklists",
      "api": {
        "endpoint": "/.netlify/functions/check-blacklist",
        "params": [
          "input"
        ]
      },
      "mcp": "check_blacklist"
    },
    {
      "name": "SURBL Checker",
      "url": "https://warminboxes.com/surbl-checker",
      "category": "Diagnostics",
      "description": "Bulk-check domains against the SURBL URI blacklist, one domain or a whole CSV",
      "api": {
        "endpoint": "/.netlify/functions/check-surbl",
        "params": [
          "domains"
        ]
      },
      "mcp": "check_surbl"
    },
    {
      "name": "Google Domain Checker",
      "url": "https://warminboxes.com/google-domain-checker",
      "category": "Diagnostics",
      "description": "See if a domain is already tied to a Google Workspace account or clear for fresh Google inboxes",
      "api": {
        "endpoint": "/.netlify/functions/check-google-domain",
        "params": [
          "domain"
        ]
      },
      "mcp": "check_google_domain"
    },
    {
      "name": "SPF Checker & Generator",
      "url": "https://warminboxes.com/spf-checker",
      "category": "DNS & Authentication",
      "description": "Recursive lookup counting against the 10-lookup limit",
      "api": {
        "endpoint": "/.netlify/functions/check-spf",
        "params": [
          "domain"
        ]
      },
      "mcp": "check_spf"
    },
    {
      "name": "DKIM Checker",
      "url": "https://warminboxes.com/dkim-checker",
      "category": "DNS & Authentication",
      "description": "Auto-scans 26 common selectors",
      "api": {
        "endpoint": "/.netlify/functions/check-dkim",
        "params": [
          "domain",
          "selector"
        ]
      },
      "mcp": "check_dkim"
    },
    {
      "name": "DMARC Checker",
      "url": "https://warminboxes.com/dmarc-checker",
      "category": "DNS & Authentication",
      "description": "Policy, tags, and verdicts explained",
      "api": {
        "endpoint": "/.netlify/functions/check-dmarc",
        "params": [
          "domain"
        ]
      },
      "mcp": "check_dmarc"
    },
    {
      "name": "BIMI Checker",
      "url": "https://warminboxes.com/bimi-checker",
      "category": "DNS & Authentication",
      "description": "Logo record, SVG, VMC validation",
      "api": {
        "endpoint": "/.netlify/functions/check-bimi",
        "params": [
          "domain"
        ]
      },
      "mcp": "check_bimi"
    },
    {
      "name": "MTA-STS Checker",
      "url": "https://warminboxes.com/mta-sts-checker",
      "category": "DNS & Authentication",
      "description": "DNS record, policy file fetch, enforce mode, TLS-RPT",
      "api": {
        "endpoint": "/.netlify/functions/check-mta-sts",
        "params": [
          "domain"
        ]
      },
      "mcp": "check_mta_sts"
    },
    {
      "name": "DNS Checker",
      "url": "https://warminboxes.com/dns-checker",
      "category": "DNS & Authentication",
      "description": "All record types",
      "api": {
        "endpoint": "/.netlify/functions/check-dns",
        "params": [
          "domain",
          "type"
        ]
      },
      "mcp": "check_dns"
    },
    {
      "name": "CNAME Checker",
      "url": "https://warminboxes.com/cname-checker",
      "category": "DNS & Authentication",
      "description": "Follow a full CNAME chain to find why a tracking domain will not resolve",
      "api": {
        "endpoint": "/.netlify/functions/check-cname",
        "params": [
          "host",
          "expected"
        ]
      },
      "mcp": "check_cname"
    },
    {
      "name": "Nameserver Checker",
      "url": "https://warminboxes.com/nameserver-checker",
      "category": "DNS & Authentication",
      "description": "Bulk NS lookup with DNS provider identification",
      "api": {
        "endpoint": "/.netlify/functions/check-nameservers",
        "params": [
          "domains"
        ]
      },
      "mcp": "check_nameservers"
    },
    {
      "name": "Record Generator",
      "url": "https://warminboxes.com/record-generator",
      "category": "DNS & Authentication",
      "description": "Correct SPF/DKIM/DMARC with ESP presets",
      "api": null,
      "mcp": null
    },
    {
      "name": "Domain Expiry Checker",
      "url": "https://warminboxes.com/domain-expiry-checker",
      "category": "DNS & Authentication",
      "description": "Expiration monitoring via RDAP, falling back to WHOIS for ccTLDs that publish no RDAP service",
      "api": {
        "endpoint": "/.netlify/functions/check-domain-expiry",
        "params": [
          "domain"
        ]
      },
      "mcp": "check_domain_expiry"
    },
    {
      "name": "ESP Segmentation",
      "url": "https://warminboxes.com/esp-segmenter",
      "category": "Lists & Planning",
      "description": "Split lead lists by Google, Microsoft, and gateway-protected inboxes via MX",
      "api": {
        "endpoint": "/.netlify/functions/segment-esp",
        "params": [
          "domains"
        ]
      },
      "mcp": "segment_esp"
    },
    {
      "name": "CSV List Cleaner",
      "url": "https://warminboxes.com/csv-cleaner",
      "category": "Lists & Planning",
      "description": "Dedupe, role/disposable removal, in-browser",
      "api": null,
      "mcp": null
    },
    {
      "name": "Sequencer CSV Converter",
      "url": "https://warminboxes.com/sequencer-csv-converter",
      "category": "Lists & Planning",
      "description": "Convert lead CSVs between Instantly, Smartlead, and Email Bison formats",
      "api": null,
      "mcp": null
    },
    {
      "name": "Verification Waterfall Calculator",
      "url": "https://warminboxes.com/waterfall-calculator",
      "category": "Lists & Planning",
      "description": "Cheapest verifier order and cost per usable email",
      "api": null,
      "mcp": null
    },
    {
      "name": "Domain & Inbox Planner",
      "url": "https://warminboxes.com/inbox-planner",
      "category": "Lists & Planning",
      "description": "Target volume to exact domains/inboxes with ramp-up",
      "api": null,
      "mcp": null
    },
    {
      "name": "Inbox Rotation Planner",
      "url": "https://warminboxes.com/inbox-rotation-planner",
      "category": "Lists & Planning",
      "description": "Two-batch rotation schedules",
      "api": null,
      "mcp": null
    },
    {
      "name": "Unsubscribe Generator",
      "url": "https://warminboxes.com/unsubscribe-generator",
      "category": "Lists & Planning",
      "description": "Compliant footers (CAN-SPAM/GDPR)",
      "api": null,
      "mcp": null
    },
    {
      "name": "CSV Combiner",
      "url": "https://warminboxes.com/csv-combiner",
      "category": "Lists & Planning",
      "description": "Merge several lead CSVs into one, deduped, with mismatched headers reconciled",
      "api": null,
      "mcp": null
    },
    {
      "name": "Infrastructure Calculator",
      "url": "https://warminboxes.com/calculator",
      "category": "Lists & Planning",
      "description": "Sends per day to the exact inbox and domain count, with cost",
      "api": null,
      "mcp": null
    },
    {
      "name": "ESP Calculator",
      "url": "https://warminboxes.com/esp-calculator",
      "category": "Lists & Planning",
      "description": "Upload a list and get the infrastructure built for the ESPs it actually contains",
      "api": {
        "endpoint": "/.netlify/functions/segment-esp",
        "params": [
          "domains"
        ]
      },
      "mcp": "segment_esp"
    }
  ]
}