Reply.io email service provider (ESP)
According to Live Direct Marketing's daily Tranco top-1M scan (September 12, 2026), Reply.io is the email service provider (ESP) for 84 domains — 0.01% of 629,828 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Key facts
- 84 domains in the Tranco top-1M use Reply.io (0.01% of SPF-publishing domains).
- Snapshot date: 2026-09-12 — recomputed every day.
- Strongest TLD: .com (81.0% of its domains).
- Most co-used service: Google Workspace.
- Directory category: email service provider.
Why Reply.io appears in this category
Reply.io — Ukrainian sales engagement and cold-email automation.
We classify it as a email service provider from include: mechanisms in the SPF record matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.
Reply.io is a sales engagement platform that provides email services for outbound prospecting campaigns. It operates as an email service provider for teams running coordinated outreach workflows, commonly integrated with Google Workspace.
Reply.io's footprint is concentrated in smaller businesses and independent teams using .com domains, rather than Fortune 500 deployments. For anyone sending or receiving email, this means Reply.io represents a significant portion of automated business outreach, and its proper configuration—SPF records, DKIM signing, DMARC policy—affects how mail systems classify and route this traffic.
Where Reply.io sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 2 | 2.4% |
| Top 100,000 | 13 | 15.5% |
| Top 1,000,000 | 69 | 82.1% |
| Unranked | 0 | 0.0% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 68 | 81.0% | |
| .co | 7 | 8.3% | |
| .io | 3 | 3.6% | |
| .net | 2 | 2.4% | |
| .build | 1 | 1.2% | |
| .group | 1 | 1.2% | |
| .eu | 1 | 1.2% | |
| .cc | 1 | 1.2% |
What Reply.io users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 84 domains.
| Type | Service | Domains | Share of Reply.io users |
|---|---|---|---|
| Mailbox | Google Workspace | 72 | 85.7% |
| Mailbox | Microsoft 365 | 4 | 4.8% |
| Mailbox | Mimecast | 3 | 3.6% |
| Mailbox | Self-Hosted | 2 | 2.4% |
| Mailbox | 1&1 IONOS | 1 | 1.2% |
| Mailbox | OVH Mail | 1 | 1.2% |
| ESP | HubSpot | 30 | 35.7% |
| ESP | Zendesk | 18 | 21.4% |
| ESP | Amazon SES | 17 | 20.2% |
| ESP | Mailchimp | 16 | 19.0% |
Authentication via Google Workspace
Reply.io deployments frequently relay outbound mail through Google Workspace's SMTP services, meaning sender reputation is established jointly by the Google Workspace account and Reply.io's infrastructure. This arrangement centralises authentication—the sending domain's SPF record typically includes Google's SPF token—but distributes reputation risk: high-volume prospecting from a shared Google Workspace account can affect both the individual domain and Google Workspace's broader sending reputation. Administrators and senders should monitor bounce rates and feedback loops closely when using Reply.io over Google Workspace SMTP.
See the full Reply.io data page (KPI cards, trend, sample domains) →
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Frequently asked questions
Is Reply.io traffic considered spam, and should I whitelist it?
Reply.io itself is not a spam service—it is a legitimate sales platform—but individual campaigns can be misconfigured or abused. Rather than blanket whitelisting, mail administrators should evaluate Reply.io senders based on authentication compliance (SPF, DKIM, DMARC), list management practices, and complaint feedback loops.
How many domains use Reply.io?
84 domains in the Tranco top-1M use Reply.io as their email service provider (ESP) as of September 12, 2026 (0.01% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Is Reply.io common enough to affect email deliverability testing?
Reply.io accounts for 0.01% of SPF-publishing domains in the top 1M. Whether you should seed a test mailbox there depends on how much of your audience it represents — the co-usage table above shows the services it appears alongside most.
Which countries or TLDs use Reply.io most?
Reply.io's largest TLD is .com (81.0% of its domains); it appears across 8 TLDs in total.