Hey folks! Been setting up a new monitoring dashboard for our side project and realized how much the free threat intel landscape has shifted. With so many feeds out there, it's tough to know which ones are still reliable and low-maintenance for a small team without a dedicated security person.
I've been testing a few over the last month, focusing on feeds that are easy to integrate (think simple blocklists for firewalls or WAFs) and have decent documentation. Here's my shortlist so far:
* **OpenPhish** – Still a workhorse for active phishing URLs. I pipe this into our WAF's blocklist. The free feed is real-time, but the big win is they have a decently low false-positive rate compared to some others.
* **AlienVault OTX** – Love the community pulse feature. You can subscribe to pulses specific to your tech stack. The API is straightforward for pulling IOC lists into our SIEM.
* **CISA's Automated Indicator Sharing (AIS)** – Requires a bit more setup (TAXII client), but the quality is high since it's from US-CERT. Great for critical vulnerabilities and known malicious IPs.
* **Blocklist.de** – Aggregates attacks from various services. I mainly use their list of IPs involved in SSH brute-force attacks. It's very "no-frills" but effective for reducing background noise.
My main criteria are: update frequency, ease of automation, and how clean the data is (I don't want to block legitimate users!). I'm also curious about any community-maintained feeds that have popped up recently.
What free feeds are you all using in 2026? Any hidden gems for small teams trying to boost their baseline defense without blowing the budget? Especially interested in feeds that play nice with cloud WAFs like Cloudflare or Fastly.
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I run a 6-person dev agency (mostly web apps for SMBs) and we've used a combo of free threat feeds for blocking malicious traffic at the edge for about two years now.
My comparison based on integrating them into Cloudflare and a small ELK stack:
**Maintenance Overhead:** OpenPhish needs the least babysitting. I update the blocklist via their API weekly with a cron job, and it's been a true set-and-forget. AlienVault OTX requires more filtering; you'll get 10x more IOCs daily and need to tune by pulse reputation.
**Integration Effort:** CISA AIS is the hardest by far. Getting a TAXII client (like cabby) running reliably took me half a day. The others are simple GET requests or downloadable lists. Blocklist.de's direct import into our edge firewall took 15 minutes.
**Signal-to-Noise for SMBs:** Blocklist.de is noisy for us - about 30% of flagged IPs were from benign scanning services we don't care about. CISA's feed had the lowest false positive rate for us, but also the lowest volume (maybe 50 new entries a week).
**Hidden Cost/Limitation:** The "cost" for AlienVault OTX is data volume. Their free tier allows 10,000 submissions per day *total* (submitting + pulling), which we hit once when experimenting. You must monitor usage.
I'd recommend OpenPhish paired with CISA AIS. Use OpenPhish for real-time URL blocking and CISA for high-confidence IPs. If your priority is speed of setup, go with OpenPhish and Blocklist.de first. If false positives are your biggest fear, swap Blocklist.de for CISA and accept the setup time.
dk