Email Warmup API And Deliverability Platform For ESPs & Email Infrastructure

An ESP sends email on behalf of businesses, through a dashboard, an email API or an SMTP relay, on its own servers and IP addresses. It's the platform a brand uses for campaigns and automated flows, which is why marketing mail sent this way is called ESP email marketing. ESP email providers also include email delivery service providers for transactional mail and email relay service providers for SMTP. The ESP email meaning is the same everywhere: mail leaves on the provider's infrastructure, not the brand's own server.

An email warmup API lets software create, start, pause and monitor email warm-up automatically. Platforms use one when a dashboard can't keep up with thousands of customer accounts.

Look at the email headers of a message you sent, or run your domain through an MX record lookup. The headers show which servers sent the message, and the "Received" and DKIM signature lines usually name the ESP. MX records show who hosts your inbox, which may be a different company. Warmy's free Email Header Analyzer and MX Record Lookup do both in seconds.

No. A corporate or business email service provider, such as Google Workspace or Microsoft 365, hosts employees' mailboxes for one-to-one email. An ESP sends bulk and automated email on behalf of businesses. A business email service provider comparison looks at storage, security and collaboration; an ESP comparison looks at sending infrastructure, deliverability and automation. Many companies use both.

It depends on your volume, the type of email you send and how much control you need. Whichever email marketing ESP you choose, inbox placement depends on your own domain reputation, authentication and list quality as much as on the platform. Warmy works alongside any ESP, so you can switch providers without starting your deliverability over.

Usually because of the sender, not the ESP: a cold or brand new domain, missing SPF, DKIM or DMARC, old or purchased lists, or a sudden jump in volume. On shared IPs, one customer's complaints can affect others too. Warm-up, placement testing and reputation monitoring catch these causes before mailbox providers act on them.

Warmy connects a mailbox or domain to its warmup network. Real inboxes receive warmup emails, open them, reply and move them out of spam, sending positive signals to mailbox providers. Warmup activity starts small and rises step by step, so the domain can build sender reputation before it carries real email campaigns.

Plan for two to four weeks before a new domain sends at full volume, longer for high targets. Warmy sets the ramp automatically and slows it if a provider pushes back. The free Warm-Up Volume Calculator helps size the schedule for each customer.

Platforms with thousands of customer accounts need more than a dashboard that promises unlimited inboxes. They need to create, pause and monitor mailboxes programmatically. The API connects multiple mailboxes per call and can launch hundreds at once, and we size the setup for large customer bases on a demo call. The free Mailbox Calculator helps estimate mailbox needs for outbound customers.

No. The number of placement tests grows with each plan rather than being unlimited tests on every tier. Book a demo to find the plan that fits your test volume.

Yes. Warm-up builds reputation for the domain and the IP the mail is sent from. For new dedicated IPs, a Seed List added to real campaigns generates engagement while volume ramps, so the IP builds trust on actual traffic.

No. Warmy isn't an ESP and doesn't relay your customers' mail. It sits beside your sending infrastructure and handles warm-up, testing, monitoring and authentication checks.

Yes, through the API. You can build warm-up, placement scores and reputation alerts into your own product, so customers experience them as features of your platform, with seamless integration into the onboarding flow you already have.

Yes. Google Workspace and Microsoft 365 mailboxes connect through OAuth 2.0, and any other email account connects over SMTP/IMAP.

Warm up new senders before they reach full volume, verify imported lists, keep complaint rates well below 0.3%, and separate high-risk senders into their own pools. Warmy's per-domain reputation monitoring shows which customer is causing trouble, so you can act on one account instead of the whole pool.

Yes. Cold outreach platforms connect every mailbox their customers use to send cold email campaigns, warm them up before the first sequence, and use reputation alerts to pause a mailbox before it burns the domain.

Yes. Gmail, Yahoo and Microsoft require SPF, DKIM and DMARC from bulk senders, and missing or misaligned records are among the most common reasons customer campaigns are rejected. Warmy's DNS health checks show which records are wrong on each domain and what to publish instead.

No. Warm-up is one part of the platform. Warmy also runs inbox placement tests, monitors domain and IP reputation and blocklists, checks SPF, DKIM and DMARC, verifies lists and includes Adeline, an AI deliverability agent. Together they cover email deliverability end to end.

Warmy accesses the mailboxes and domains you connect, with AES-256 encryption at rest, TLS 1.2+ in transit and OAuth 2.0 for Google Workspace and Microsoft 365. A DPA is available, and our Security & Trust page covers access controls and data handling for your vendor review.

Plans start from $49/month. There's no free plan, but you can start a 7-day free trial with no credit card required. Every plan and price is visible in your dashboard once the trial starts, and API access is included in every plan.