GreyNoise API
GreyNoise API — classify internet background noise from mass scanners and bots, reducing SIEM alert fatigue by identifying and filtering benign and malicious internet-wide scanning activity.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
TLS enforced. Simple API key authentication. SOC2 certified. Security-focused company with appropriate operational security. Data used by major SOC teams globally.
⚡ Reliability
Best When
Security agents need to reduce alert fatigue by rapidly classifying whether an IP is engaged in mass internet scanning versus targeted activity.
Avoid When
You need comprehensive threat intelligence beyond IP reputation — GreyNoise is narrow but deep on mass scanning context.
Use Cases
- • Security agents filtering SIEM alerts by checking if source IPs are known internet scanners (noise)
- • Enriching IOCs — agents augmenting threat intel with GreyNoise context on whether an IP is mass-scanning or targeted
- • SOC automation — agents dismissing alerts where source is known benign scanner (Shodan, Censys, security researchers)
- • Blocking decisions — agents checking if IP is classified as malicious scanner before applying firewall rules
- • Threat hunting — agents querying GreyNoise GNQL (query language) to find all IPs scanning specific ports/CVEs
Not For
- • Comprehensive threat intelligence — GreyNoise focuses on mass scanning, not APT or targeted threat actors
- • Endpoint or malware intelligence — use VirusTotal or CrowdStrike for file/malware intel
- • Historical IP attribution — GreyNoise data is 30-90 day rolling window, not historical permanent records
Interface
Authentication
API key via key header. Community tier has restricted access. Enterprise tier unlocks full context API, bulk lookups, and GNQL queries.
Pricing
Community API is free and useful for basic noise filtering. Full threat context and bulk operations require enterprise subscription.
Agent Metadata
Known Gotchas
- ⚠ 404 response for an IP means GreyNoise has no data — it's not necessarily malicious, just not observed scanning
- ⚠ Community API only returns noise/not-noise classification — full context (tags, CVEs, actors) requires enterprise
- ⚠ Data freshness: GreyNoise classifies based on recent activity (last 30-90 days) — historic IPs may not appear
- ⚠ GNQL query language is GreyNoise-specific — agents must learn syntax for complex threat queries
- ⚠ IP classifications can change — cache results for no more than 24 hours in agent workflows
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for GreyNoise API.
Scores are editorial opinions as of 2026-03-06.