According to Live Direct Marketing's daily Tranco top-1M scan (July 12, 2026), FSI (JP ISP) is the mailbox provider for 252 domains — 0.04% of 658,108 domains with MX records. Detection method: primary MX record (lowest preference).
FSI is a Japanese mailbox provider and ISP offering email hosting primarily to regional businesses and smaller-to-mid-market sites across the .jp domain space. It typically operates its own MX infrastructure and offers integrated email security features through FSI Email Security, a companion product suite.
FSI's presence in the MX record marks regional Japanese recipients; this distributed footprint across smaller sites means email senders rarely encounter FSI in volume, but those targeting Japan or Japanese-speaking businesses should verify authentication compliance with FSI's filtering standards, which tend to align with Japanese regulatory preferences and regional email practices.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 0 | 0.0% |
| Top 100,000 | 4 | 1.6% |
| Top 1,000,000 | 191 | 75.8% |
| Unranked | 57 | 22.6% |
| TLD | Domains | Share | |
|---|---|---|---|
| .jp | 120 | 47.6% | |
| .com | 86 | 34.1% | |
| .co.jp | 21 | 8.3% | |
| .net | 12 | 4.8% | |
| .shop | 8 | 3.2% | |
| .ne.jp | 3 | 1.2% | |
| .link | 1 | 0.4% | |
| .me | 1 | 0.4% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 252 domains.
| Type | Service | Domains | Share of FSI (JP ISP) users |
|---|---|---|---|
| ESP | FSI Email Security | 251 | 99.6% |
| ESP | Q-Send | 132 | 52.4% |
| ESP | Repica WebCAS | 13 | 5.2% |
| ESP | Amazon SES | 7 | 2.8% |
| ESP | BizMatrix | 4 | 1.6% |
| ESP | Zendesk | 3 | 1.2% |
| ESP | Tricorn | 2 | 0.8% |
| ESP | HubSpot | 1 | 0.4% |
| ESP | SendGrid (Twilio) | 1 | 0.4% |
| ESP | Cuenote | 1 | 0.4% |
FSI Email Security applies strict sender authentication checks, prioritising DMARC, SPF, and DKIM validation across all inbound messages. Campaigns targeting FSI-hosted recipients should ensure all three protocols are correctly deployed and aligned with the sending domain; FSI's regional focus and security posture mean that authentication failures or misalignment are flagged more aggressively than at some global providers, particularly for geographically distant senders.
See the full FSI (JP ISP) data page (KPI cards, trend, sample domains) →
FSI is a Japanese ISP and mailbox provider serving regional businesses; its integrated FSI Email Security product enforces strict DMARC, SPF, and DKIM validation, requiring senders targeting Japanese recipients to ensure proper authentication alignment.
252 domains in the Tranco top-1M use FSI (JP ISP) as their mailbox provider as of July 12, 2026 (0.04% of domains with MX records), according to Live Direct Marketing's daily DNS scan.
FSI (JP ISP) accounts for 0.04% of domains with MX records 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.
FSI (JP ISP)'s largest TLD is .jp (47.6% of its domains); it appears across 8 TLDs in total.