For the complete site index, see llms.txt. Docs index: llms-docs.txt. Marketing corpus: llms-full.txt. Docs corpus: llms-full-docs.txt. Prefer markdown URLs where available (append .md).. Product skill: skill.md. Pricing: pricing.md. Docs MCP: /docs/mcp.

Free Tools

Free Domain Warmup Checker

New domains get flagged as spam. Paste any domain to see its warmup stage, its deliverability risk, and whether SPF, DMARC and MX are ready before you send. Free, no sign-up.

Best features

Why choose Reloop's domain warmup checker?

Free, no account needed, and based on the same warmup caps Reloop enforces for every new domain.

100% Free & No limits

This checker is free. It needs no signup and has no credits or expiry.

Clear warmup stage

Know exactly where you are: Too New (0–7 days), Cold (8–30 days), Warming (31–90 days), or Established (90+ days).

Setup readiness

See whether SPF, DMARC and MX are published, because age alone won't get you to the inbox.

No Account Needed

Use the checker or the API without an account or an API key.

Warmup schedule

How fast can a new domain send email?

Safe daily send caps by domain age: the same caps Reloop enforces automatically for every new domain.

Domain age
Daily cap
Status
What to do
Initial Ramp (0–7 days)
0–1 days
20 / day
Too new
Publish SPF, DKIM, DMARC. Don't send bulk or cold email yet.
2–3 days
50 / day
High risk
Begin slow warmup to engaged contacts only (no cold lists).
4–7 days
100 / day
Building
Ramp gradually. Watch bounce rate and spam complaints closely.
Volume Scaling (8–30+ days)
8–14 days
250 / day
Building
Continue ramp; monitor DMARC reports for auth failures.
15–30 days
500 / day
Maturing
Near-full volume. Keep list quality high and engagement clean.
30+ days
Plan caps
Mature
Full sending volume, subject to plan caps and engagement quality.

Manual warmup is slow and easy to get wrong.

Reloop handles the warmup for you. No credit card required.

Start free
Who is it for

Where can I use Reloop's domain warmup checker?

Anyone sending from a new domain who wants to reach the inbox, not the spam folder.

Founders & startups

  • Launch announcements
  • First product emails
  • Waitlist invites
  • Transactional email setup
  • New brand domains
  • Rebrand migrations
  • Investor updates

Sales & outreach

  • Cold email domains
  • Secondary sending domains
  • SDR inbox rollout
  • Sequence go-live checks
  • Domain rotation
  • Volume ramp planning
  • Reply rate drops

Marketing teams

  • Newsletter launches
  • Campaign domains
  • Event invitations
  • Lifecycle emails
  • ESP migrations
  • List re-engagement
  • Promo sends

Agencies & developers

  • Client domain onboarding
  • Pre-launch audits
  • DNS setup reviews
  • Deliverability tickets
  • Staging to prod cutover
  • Multi-tenant sending
  • Automated go-live gates
API integration

Integrate today in your code

One request returns the warmup stage, deliverability risk and SPF, DMARC and MX readiness for any domain. No API key or account needed.

Body

domainstringrequired
Domain or URL to inspect (e.g. stripe.com). Subdomains resolve to their registrable root; IP addresses are rejected.

Request

// No SDK, no API key: it is a plain POST.
const res = await fetch(
  "https://reloop.sh/api/tools/v1/domain-age",
  {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ domain: "stripe.com" }),
  },
);


const result = await res.json();
Sample Response
{
  "domain": "stripe.com",
  "registrableDomain": "stripe.com",
  "resolvedAt": "2026-10-12T17:46:45.966Z",
  "responseTimeMs": 211,
  "verdict": "mature",
  "headline": "This domain is 31 years, 1 month old",
  "summary": "Registered 31 years, 1 month ago (11,353 days). Domain age is completely mature and will not impact email deliverability.",
  "disclaimer": "Gmail and Outlook do not publish an exact age threshold. This evaluation provides Reloop’s sending guidance based on newly registered domain filters.",
  "age": {
    "createdAt": "1995-09-12T04:00:00.000Z",
    "ageDays": 11353,
    "expiresAt": "2027-09-11T04:00:00.000Z",
    "updatedAt": "2025-10-01T01:39:51.000Z",
    "source": "rdap"
  },
  "registry": {
    "registrar": "SafeNames Ltd.",
    "status": ["client delete prohibited", "client transfer prohibited", "client update prohibited", "server delete prohibited", "server transfer prohibited", "server update prohibited"],
    "tld": "com"
  },
  "nameservers": {
    "hosts": ["ns-705.awsdns-24.net", "ns-1087.awsdns-07.org", "ns-1882.awsdns-43.co.uk", "ns-423.awsdns-52.com"],
    "provider": "AWS Route 53",
    "kind": "production"
  },
  "emailSetup": {
    "spf": true,
    "dmarc": true,
    "dmarcPolicy": "reject",
    "mx": true
  },
  "nextStep": {
    "title": "Send high-volume email with Reloop",
    "body": "Scale your transactional and marketing emails with Reloop's developer API and SMTP infrastructure.",
    "href": "/dashboard/signup"
  },
  "warnings": []
}
AI native

Check warmup stage from your AI agent

Connect Claude, Cursor, or any MCP client to Reloop and let your agent check if a domain is ready before it sends.

MCP Server

Connect Reloop to your AI agent. Let Claude, Cursor, or Codex check a domain's warmup stage before they send.

  1. 1

    Open Connectors

    In Claude, go to Settings → Connectors and click Add custom connector. On Team and Enterprise plans an owner adds it under Organization settings first.

    Add to Claude
  2. 2

    Paste the server URL

    Name it Reloop and use this URL. Leave the advanced OAuth fields empty; Reloop registers the client automatically.

    https://reloop.sh/mcp
  3. 3

    Connect

    Click Connect, sign in to Reloop and approve the workspace. Then turn Reloop on from the tools menu in any chat.

Learn more

Developer CLI

Send email from your terminal. Test deliveries and fix configuration without a dashboard.

Reloop CLI

v0.4.2 · Send email from your terminal

$ reloop emails send \

--to user@example.com \

--subject "Welcome to Reloop" \

--json

✓ queued → sent → delivered (78ms)

{ "id": "msg_01jh8q...", "to": "user@example.com", "status": "delivered" }

$ reloop emails send --to dev@company.com █

Learn more
All tools

Explore all free email & developer tools

More free utilities for checking deliverability, DNS records, and email authentication before you hit send.

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Stop warming up manually.
Let's talk.

Reloop handles your domain warmup and watches for bounce and spam signals automatically. Start with 3,000 free emails per month.

Get started freeTalk to founder

FAQ

Frequently asked questions.

Too New (0 to 7 days) means mail will very likely be filtered. Cold (8 to 30 days) means keep volume near zero. Warming (31 to 90 days) means ramp volume up gradually. Established (90+ days) means age no longer hurts deliverability.

Yes. Mailbox providers and blocklists like Spamhaus NRD treat domains registered within the last 14 to 30 days as high-risk senders. Even perfect SPF, DKIM, and DMARC records cannot override a brand-new domain's cold-domain penalty. You need to warm up your domain gradually over 60 to 90 days before sending large email volumes.

Spammers frequently register brand-new domains, blast hundreds of thousands of unsolicited emails over 48 hours, and abandon them. To protect recipients, mailbox algorithms (and blocklists like Spamhaus NRD) automatically treat domains registered within the last 14 to 30 days as high-risk cold senders.

No. Authentication proves that the sender authorized the email, but it does not give the domain a positive sending reputation history. A 3-day-old domain with valid SPF and DMARC will still face severe inbox filtering if it suddenly sends high-volume marketing emails.

We recommend waiting at least 14 days after domain registration before beginning initial sending warmups. During the first 14 days, publish SPF, DKIM, and DMARC in DNS. Start warmups slowly between days 15 and 90, gradually scaling daily volume.

If your domain's DNS points to default registrar parking servers (e.g. Sedo, Bodis, or Namecheap parking), receiving mail servers cannot resolve production mail exchanges. Switch your nameservers to a production DNS provider (like Cloudflare, Route 53, or Google Cloud) to send email.

Reloop provides built-in SPF/DKIM/DMARC setup, gradual volume ramp-up scheduling, and real-time bounce/spam monitoring so you can safely build high sender reputation without triggering mailbox spam filters.

Yes. The checker and its API are free with no sign-up, no API key, no credits and no expiry.

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