What is 0spam (Fusionzero)?
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You're scanning a blocklist report and you spot 0spam (also called Fusionzero). Should you panic? Probably not. But let's cover what it actually is so you can make that call yourself.
0spam is a community-driven blocklist network that tracks both IP addresses and domains associated with spam and abuse. It runs three main zones: bl.0spam.org (the primary list), rbl.0spam.org (the RBL zone), and 0spam.fusionzero.com (a legacy zone that still sees some queries). Think of it like a neighborhood watch for email, built and maintained by community members rather than a large commercial organization.
What gets you listed? The three most common triggers are spam reports from community members, hits on 0spam's honeypot network (those are fake addresses set up specifically to catch senders who bought or harvested lists), and association with infrastructure that's already known for spam activity.
Impact level: low. Most major mailbox providers don't query 0spam directly. Its adoption is limited to a smaller set of mail systems, niche hosting environments, and community-run servers. That said, "low impact" doesn't mean zero impact. If your emails are failing to reach a specific recipient and nothing else explains it, a 0spam listing is worth ruling out.
Delisting is straightforward. Go to their website, request removal, and make sure you've actually fixed whatever triggered the listing first. Requesting removal without fixing the root cause just gets you relisted.
If you want to see your full blocklist picture at once, you can run your domain or IP through our free blocklist checker. It covers the lists that matter most, so you're not chasing ghosts one by one.
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