WarmEnvelopes
WarmEnvelopes is a web service that schedules real warm-up emails through a user's Resend account to inboxes the user controls.
What WarmEnvelopes is
WarmEnvelopes is a web service that schedules real warm-up emails through a user's Resend account to inboxes the user controls. It is intended to build sending history for domains the user owns or is authorized to manage, using inboxes owned by the user or whose owners consented to receive messages. Setup requires a verified sending domain and a Resend API key, with a separate key stored for each domain. A scheduler runs every 30 minutes and spreads the daily target across the day. The service varies sender names and templates from a library of more than 1,000 independently written messages in several languages. Its dashboard tracks progress against the daily target, and its log records the sender, template, delivery status, and any error. The Free plan costs €0 and permits 4 emails per day per domain across up to 10 domains. Pro costs €9 / month and allows users to set a starting volume, daily increase, and maximum of 1,000 emails per day. A separate no-sign-up checker reviews SPF, DKIM, DMARC, MX, and blocklist status. WarmEnvelopes does not guarantee inbox placement or resolve DNS, recipient-list, or spam-content problems.
Good
- Free plan allows 4 emails per day per domain.
- Supports up to 10 domains on the Free plan.
- Sending log records delivery status and errors.
- Free domain checker checks SPF, DKIM, DMARC, MX, and blocklists.
Watch out
- Requires a verified sending domain and Resend API key.
- Does not guarantee inbox placement.
- Does not fix DNS, recipient-list, or spam-content problems.
- Spam monitoring is not available.
Who it suits
WarmEnvelopes is for people managing their own or authorized domains who can send to consenting inboxes through Resend. Its configurable Pro ramp may suit users who need to set daily sending volumes.
Verdict
WarmEnvelopes provides scheduled, logged warm-up mail with a free option and configurable Pro volumes. It depends on a verified domain, Resend, and appropriate recipient inboxes, and it makes no inbox-placement guarantee.
Plans and prices
From WarmEnvelopes's own pricing page, checked 15 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free | Free | 4 warm-up emails/day per domain · up to 10 domains · sending log and filters · no credit card · free forever |
| Pro | €9 a month | 1–50 starting emails/day · 0–50 daily increase · up to 1,000 emails/day · up to 10 domains · sending log and filters · Resend quota applies · billed monthly via Stripe |
The facts
Each one read from WarmEnvelopes's own pages, with the date it was checked.
What it does
- Acceptable use
- Users may only configure domains they own or are authorized to manage and recipient inboxes whose owners consent to receive the messages.checked 15 Oct 2026
- Account access
- Users sign in with Google.checked 15 Oct 2026
- Authentication
- Warm-up messages are described as SPF, DKIM, and DMARC aligned when accepted by the receiving mailbox.checked 15 Oct 2026
- Compliance
- The privacy policy gives users GDPR access, correction, deletion, restriction, objection, and portability rights.checked 15 Oct 2026
- Data handling
- The privacy policy says WarmEnvelopes does not read users' inboxes, sell or share data for advertising, or use analytics cookies unless accepted.checked 7 Oct 2026
- Data stored
- Stored configuration includes domains, Resend API keys, ramp settings, and recipient inbox addresses.checked 15 Oct 2026
- Domain checker
- A free checker without sign-up tests SPF, DKIM, DMARC, MX, and blocklist status.checked 15 Oct 2026
- External context: Gmail monitoring
- Google recommends monitoring server responses, spam rate, and sending-domain reputation while increasing volume.checked 15 Oct 2026
- External context: Gmail pacing
- Google advises senders to start with low volume, increase gradually, send consistently, and avoid bursts.checked 15 Oct 2026
- External context: Gmail spam threshold
- Google's sender FAQ says senders should keep spam rates below 0.1% and avoid reaching 0.3% or higher.checked 15 Oct 2026
- External context: industry guidance
- M3AAWG publishes sender best-practice guidance covering technical and policy aspects of commercial electronic messaging.checked 15 Oct 2026
- External context: Resend API
- Resend's pricing documentation lists a RESTful API and official SDKs as sending capabilities.checked 15 Oct 2026
- External context: Resend paid pricing
- Resend lists Pro at $20 per month for 50,000 emails and no daily email limit.checked 15 Oct 2026
- External context: Spamhaus ZRD
- Spamhaus says newly observed domains are placed on its Zero Reputation Domain list for 24 hours and then removed automatically.checked 15 Oct 2026
- Integration
- It requires a verified sending domain and a Resend API key, and each domain stores its own key.checked 7 Oct 2026
- Intended audience and use
- The service is for warming domains the user owns or is authorized to manage, using recipient inboxes they own or whose owners consented to receive warm-up mail.checked 7 Oct 2026
- Limit: deliverability scope
- WarmEnvelopes says it does not repair broken DNS, poor recipient lists, or spam-like content.checked 15 Oct 2026
- Limit: inbox guarantee
- The service expressly says it cannot guarantee inbox placement or delivery rates.checked 15 Oct 2026
- Limit: provider support
- The documented sending integration is Resend, so the service requires a Resend account and does not present support for other ESPs.checked 15 Oct 2026
- Limit: quota consumption
- Warm-up messages consume the customer's Resend sending quota because they leave through the customer's API key.checked 15 Oct 2026
- Limits
- It does not guarantee inbox placement or fix broken DNS, poor recipient lists, or spam-like content.checked 7 Oct 2026
- Message format
- Warm-up messages are described as short plain correspondence without images, attachments, tracking pixels, or marketing language.checked 15 Oct 2026
- No simulated engagement
- WarmEnvelopes says it does not use shared inbox pools, bot opens, scripted replies, or automated spam-folder rescues.checked 15 Oct 2026
Money
- External context: Resend free quota
- Resend's Free plan allows 3,000 emails per month and 100 emails per day, so WarmEnvelopes sends share that quota.checked 15 Oct 2026
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