Security – Free-tier APIs
52 Free-tier APIs in the category Security. Free public web APIs that developers and AI agents can call. Entries come from the open public-apis list; each link was checked automatically (HTTP status) on the date shown, which says the site responded, not that the API is good.
Agent Verifier
Self-check for AI agents: verifies Web Bot Auth signatures and shows how a request looks
Application Environment Verification
Android library and API to verify the safety of user devices, detect rooted devices and other risks
BitWarden
Best open-source password manager
Botd
Botd is a browser library for JavaScript bot detection
Bugcrowd
Bugcrowd API for interacting and tracking the reported issues programmatically
Censys
Search engine for Internet connected host and devices
CISA Known Exploited Vulnerabilities
CISA KEV catalog of actively exploited CVEs as JSON, filterable by vendor, with CWE and due dates
Complete Criminal Checks
Provides data of offenders from all U.S. States and Pureto Rico
CompliAPI
Screen crypto addresses, emails, websites, IDs and countries against OFAC, EU, UK sanctions lists
CSR.plus
Generate certificate signing requests and private keys without OpenSSL
dead-drop
Ephemeral zero-knowledge encrypted data sharing
Domain Intelligence
DNS, WHOIS/RDAP, SSL, subdomain enumeration, and email security in one parallel call
EmailRep
Email address threat and risk prediction
Escape
An API for escaping different kind of queries
FilterLists
Lists of filters for adblockers and firewalls
FingerprintJS Pro
Fraud detection API offering highly accurate browser fingerprinting
FOFA
Search engine for Internet connected assets and devices
FraudLabs Pro
Screen order information using AI to detect frauds
FullHunt
Searchable attack surface database of the entire internet
GreyNoise
Query IPs in the GreyNoise dataset and retrieve a subset of the full IP context data
HackerOne
The industry’s first hacker API that helps increase productivity towards creative bug bounty hunting
HaveIBeenPwned
Passwords which have previously been exposed in data breaches
Hybrid Analysis
File and URL malware analysis powered by Falcon Sandbox
Intelligence X
Perform OSINT via Intelligence X
IPGuardian
Check IP addresses against 140+ public threat intelligence blocklists
IPLogs
Free VPN, proxy, Tor and datacenter IP detection. 13 sources, active probing
IPScanner
IP network class (residential, mobile, hosting, VPN, residential proxy, Tor) with a confidence score
isMalicious
Reputation of IPs, domains, URLs and file hashes from aggregated threat feeds, plus CVE lookups
LoginRadius
Managed User Authentication Service
Maskbreak
Detect VPNs, proxies, Tor, bots and antidetect browsers at signup, login and checkout
Microsoft Security Response Center (MSRC)
Programmatic interfaces to engage with the Microsoft Security Response Center (MSRC)
Mozilla http scanner
Mozilla observatory http scanner
Mozilla tls scanner
Mozilla observatory tls scanner
National Vulnerability Database
U.S. National Vulnerability Database
Neetix Liveliness
Face liveness, presentation-attack detection and 1:1 face match for identity verification
OSV
Open source vulnerability database and distributed triage infrastructure
Passwordinator
Generate random passwords of varying complexities
PhishStats
Phishing database
Presend
Security and developer utility API -- malware, vulnerability, and domain checks, no signup
Privacy.com
Generate merchant-specific and one-time use credit card numbers that link back to your bank
Pulsedive
Scan, search and collect threat intelligence data in real-time
Sealed Rose
AI media forensics and synthetic content verification for video, audio, image, and text
SecurityTrails
Domain and IP related information such as current and historical WHOIS and DNS records
Shodan
Search engine for Internet connected devices
Spyse
Access data on all Internet assets and build powerful attack surface management applications
SSL Domain Health Check
SSL certificate validity, domain WHOIS status, and DNS record checks for any domain
SSL Labs
Deep SSL/TLS server analysis with A+ to F grading
ThreatCluster
Threat intelligence: incident clusters, validated IOCs, CVEs, ransomware leak-site victims
UK Police
UK Police data
URLhaus
Database of malicious URLs used for malware distribution
VPNDetection
Check whether an IPv4 or IPv6 address belongs to VPN infrastructure, no key needed
VulDB
VulDB API allows to initiate queries for one or more items along with transactional bots