SFR is a French ISP mailbox. Across 25,403 SFR addresses verified by BounceZero between April and October 2026, 28.7% were invalid, 0.0% catch-all, 16.8% unknown and 42.2% confirmed valid. Catch-all and unknown together mean a large share cannot be confirmed.
Every SFR address BounceZero verified for customers between April and October 2026, beside the corpus benchmarks. The remainder of each row to 100% is risky and role results.
| Segment | Addresses | Invalid | Catch-all | Unknown | Confirmed valid |
|---|---|---|---|---|---|
| SFR | 25,403 | 28.7% | 0.0% | 16.8% | 42.2% |
| All non-freemail domains (business and ISP) | 6,514,884 | 14.5% | 2.3% | 27.0% | 32.6% |
| Business domains only (consumer ISP and freemail excluded) | 1,269,919 | 22.9% | 9.4% | 22.5% | 40.3% |
| All freemail | 1,415,154 | 17.6% | 1.1% | 2.1% | 74.0% |
| All .fr addresses | 119,582 | 12.1% | 0.5% | 9.3% | 47.5% |
Non-freemail includes consumer ISP mailboxes; a business-only cut is on the benchmarks page. Method and every other cut: Lead List Quality Benchmarks 2026. Risky and role on the SFR row: 12.3%.
SFR answers most probes clearly. Close to three in ten addresses verify as invalid and about one in six returns unknown, with four in ten confirmed valid. French ISP mailboxes churn with broadband contracts, and SFR has migrated platforms more than once.
SFR is one of the three large French broadband providers and its mailboxes follow the subscription. The provider migrated platforms during its acquisition by Altice, which closed dormant accounts and explains the high confirmed-invalid rate. On French B2B lists the address marks artisans and sole traders. CNIL rules require consent for individuals, and the professional exception applies only where the address was published for professional purposes.
On confirmed-invalid rate, SFR ranks 10 of 29 providers in the corpus, just behind Xtra (Spark) at 29.0%, ahead of MindSpring at 25.6%.
On unknown rate, SFR ranks 15 of 29 providers in the corpus, just behind AOL at 19.9%, ahead of Hotmail Netherlands at 8.7%.
On confirmed-valid share, SFR ranks 10 of 29 providers in the corpus, just behind Telefónica at 48.5%, ahead of Bbox (Bouygues Telecom) at 38.1%.
How to read these rates: they are BounceZero's probe outcomes on customer lists over April to October 2026, not a census of SFR mailboxes. Unknown and catch-all measure what verification could not confirm, which depends on the provider's gateway policy during the window as much as on the addresses. The lists are the ones customers chose to upload, so segments dominated by a few large uploads carry their age and source. Method and limitations: benchmarks page.
SFR leaves 16.8% of addresses unconfirmed. Hold them out of cold volume, re-check in a week, and move anything still unknown to a second channel.
Roughly one in 3 SFR addresses is dead, against about one in 7 across non-freemail lists.
Catch-all is negligible on SFR (0.0%); when this provider does return valid, the mailbox accepted the probe itself rather than a blanket accept.
Just over 42% confirmed valid: reachable today, re-verified before every send, since only 19.2% of addresses were still valid 90 days after a check in BounceZero's decay study.
Trust the invalid verdicts and re-check the unknowns once. SFR contacts on a B2B list are usually sole traders; consent rules for individuals under French law apply.
Role addresses such as info@ and sales@ make up 0.0% of SFR addresses in the corpus. Role addresses are rare here, as expected for a mailbox provider.
All provider and country cuts, with method
Every domain in the benchmark set
Sources ranked by data quality
Thresholds and filtering at this provider
The country segment SFR belongs to
28.7% of 25,403 SFR addresses verified by BounceZero between April and October 2026 were confirmed invalid, against 14.5% across non-freemail domains and 17.6% across freemail.
16.8%. Unknown means the mailbox could not be confirmed either way, usually because the gateway deferred the probe. BounceZero refunds unknown results; re-check after a week or use a second channel.
Not in practice: 0.0% of SFR addresses returned catch-all, so a valid verdict means the mailbox exists.
42.2% confirmed valid at verification time. Keep bounces under 2% and complaints under 0.3% on the send, and re-verify the segment before every send.
Upload the file and see valid, invalid, catch-all and unknown per row, with the SFR segment against this benchmark. 100 free checks a month, unknowns refunded.
Ayoub built BounceZero's 5-stage validation pipeline, its dedicated BGP-announced IP infrastructure, and the Patroni HA PostgreSQL cluster behind every verification. Previously built high-volume email delivery infrastructure. Trained at 1337 Benguerir (École 42 network, 2019). Open-source: bgp_analyzer.
Invalid, catch-all and unknown rates per email provider and country domain, 2026
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