Best Free Security Tools

Malware and URL analysis API (Google) — free community tier: 500 requests/day, 4 requests/minute. Scan files, URLs, domains, IPs against 70+ antivirus engines. Non-commercial use only

Screen an order transaction for credit card payment fraud. This REST API will detect all possible fraud traits based on the input parameters of an order. The Free Micro plan has 500 transactions per month. Best for open source projects.

Code quality and security analysis — free and unlimited for open-source projects, 15+ languages, CI/CD integration. Formerly SonarCloud. Best for unlimited usage needs. Note — 2026-04-01: SonarQube Cloud introduced more granular Team tier pricing with differentiated feature access. Free tier for open-source projects remains. Paid tiers restructured for clearer scaling path from small teams to enterprise Source ↗

Tools and services for implementing end-to-end encryption, database protection, IoT security, and more in your digital solution. Free for applications with up to 250 users.

Free automated dependency updates and vulnerability alerts for all GitHub repos. Generates pull requests for updates across 30+ ecosystems (npm, pip, Maven, Go, Docker, etc.). Best for open source projects.

CNCF Graduated (Apache 2.0) runtime security tool. Monitors Linux syscalls and Kubernetes events to detect threats in containers, hosts, and cloud environments in real time.

Developer security — 200 open-source SCA tests/month, 100 SAST (Snyk Code) tests/month, 100 container tests/month, 300 IaC tests/month. Unlimited contributing developers. Code and dependency scanning across all products. Best for open source projects and unlimited usage needs.

All-in-one appsec platform covering SCA, SAST, CSPM, DAST, Secrets, IaC, Malware, Container scanning, EOL,... Free plan includes two users, scanning of 10 repos, 1 cloud, 2 containers & 1 domain.

Free plan with 5 scan hours/month for web application and API vulnerability scanning, up to 3 users, full API access. No credit card required.

Superseded: As of 2026-09-07, socket.dev/pricing reads: Free: $0 per month, per developer. Unlimited developers & repos. 1,000 scans per month. 500 API quota per hour. 3 members, 1 repository label. We are not publishing our stored Socket.dev terms beside it — our own pricing change record, discovered 2026-09-07, names them as the previous ones. Read what we recorded ↓ Note — discovered 2026-09-07: The free tier now has 3 members instead of 5, and 500 API quota per hour instead of unlimited. It also includes Socket Basics - SAST, Secrets, and Container scans. Source ↗

Cloud-first, developer-friendly security platform prevents data breaches in .NET and Java applications

A free mobile-friendly tool that offers a variety of randomly generated keys and passwords you can use to secure any application, service, or device.

Open source license compliance and software composition analysis (SCA). Free tier: 5 projects, 10 contributing developers, 1 release group, 5 dependency levels, container scanning, SBOM export, API access Best for open source projects.

A simple, intuitive web app for analyzing and decoding/encoding data without dealing with complex tools or programming languages. Like a Swiss army knife of cryptography & encryption. All features are free to use, with no limit. Open source if you wish to self-host. Best for open source projects and unlimited usage needs.

Free autonomous security platform that finds, validates and fixes insecure code and packages across +20 languages and frameworks. Free plan includes 10 repos, 10 PR scans/month, and 10 SAST auto fixes. Features: AI SAST, Logic/Auth Scanning, Dependency Scanning, Secrets Detection, Container Scanning, IaC Scanning. Best for open source projects.

Open source (Apache 2.0) IaC static analysis. Scans Terraform, CloudFormation, Kubernetes, Helm, Dockerfile, and 10+ frameworks for misconfigurations. No usage limits. Best for open source projects.

Scan your Django site for security flaws with this free, automated checkup tool. Forked from the Pony Checkup site.

Consent management and privacy framework tool. The free tier offers most features with a limited visitor count.

Privacy and cookie policies and consent management. The free tier offers limited privacy and cookie policy as well as cookie banners.

A login security API to detect fraudulent and suspicious logins and notify your customers. Free for 1,000 logins per month.

Monitor Java, Javascript, .NET, Scala, Ruby, and NodeJS projects for security vulnerabilities in dependencies. Free for one private project, unlimited projects for open source. Best for open source projects and unlimited usage needs.

Open source (MIT) vulnerability scanner with YAML-based template system. 9,000+ community templates for web apps, APIs, networks, DNS, SSL. No usage limits. Best for open source projects.

Manage SSL Certificate issuance, renewal, and monitoring. Search the Certificate Transparency Logs. Free for 3 certificates and 1 user after the beta.

Open source (Apache 2.0) vulnerability scanner for container images and filesystems. Covers 20+ language ecosystems with daily-updated CVE database. Best for open source projects.

Intense analysis of the configuration of any SSL web server

Secrets detection for up to 25 developers — 420+ secret types, unlimited real-time scanning, 500 historical scan detections, CLI (ggshield) for pre-commit hooks, VSCode extension, 10K API calls/month Best for unlimited usage needs.

Open source (AGPL-3.0) automated dependency update bot. Supports 90+ package managers. Available as self-hosted CLI or free hosted GitHub/GitLab App by Mend. Best for open source projects.

Open source (Apache 2.0) multi-target vulnerability scanner for container images, filesystems, git repos, IaC, Kubernetes, SBOMs, and cloud resources. Best for open source projects.

Open source (Apache 2.0) web application security scanner. Passive/active scanning, AJAX spider, fuzzing, manual interception, CI/CD integration. No usage limits. Best for open source projects.

Device identification and fraud prevention — 1,000 API calls/month free. Browser fingerprinting, bot detection, and account fraud prevention. Useful for auth flows, anti-fraud, and bot detection in apps.

Open source (Apache 2.0) secret scanner for git repos, Docker images, S3, Slack, and 20+ sources. Detects 800+ credential types with active API verification. Best for open source projects.

Secure Enterprise-grade platform for managing environment variables and secrets. Free tier includes up to 3 applications and 150 secrets per project.

Superseded: As of 2026-08-28, semgrep.dev/pricing reads: Free Edition: Cross-file analysis with Pro rules, AI-powered detection, triage, and remediation, 60 AI credits included, Fast CI/CD deploy via Semgrep infrastructure, Scan up to 10 repositories, Maximum 10 contributors, Authentication via GitHub/GitLab. We are not publishing our stored Semgrep terms beside it — our own pricing change record, discovered 2026-08-28, names them as the previous ones. Read what we recorded ↓ Note — discovered 2026-08-28: The free tier now includes 60 AI credits and scans up to 10 repositories with a maximum of 10 contributors. Previously 50 private repos (unlimited public). Source ↗

Free SSL Certificate Authority with certs trusted by all major browsers

HTTP security header testing tool. Now integrated into MDN as HTTP Observatory.

REST API for fetching information on data breaches. Free web search; API requires subscription for some endpoints.

Free website security check and malware scanner

URL and website security scanner API — free tier: 50 private scans/day, 1,000 unlisted scans/day, 5,000 public scans/day, 1,000 search requests/day, 10,000 result requests/day

Helps implement privacy by design via audits and continuous workflows so that organizations comply with GDPR and other regulations. The free tier is limited to smaller teams and the SaaS version only.

AI-powered development security platform (rebranded from PyUp). Free: 1 codebase, 100 scans/month, 1 user, non-commercial only. Uses public vulnerability databases (Safety's proprietary 4x database requires paid plan). Email support with 48-hour response.

High confidence Indicator of Compromise(IOC) targeting public cloud infrastructure, A portion is available on github (https://github.com/unknownhad/AWSAttacks). Full list is available via API

GitHub semantic code analysis engine. Free for all public repositories with no scan limits. Supports JS/TS, Python, Java, C#, C/C++, Go, Ruby. Integrated into GitHub Actions.

Open source (MIT) secret scanner for git repositories, files, and directories. CLI tool is free with no limits. GitHub Action free for personal repos and 1 org repo. Best for personal projects and open source projects and unlimited usage needs.

Test an SSL/TLS service for secure server configuration, certificates, chains, etc. Not limited to HTTPS.

Sync your .env files, quickly & securely. Stop sharing your .env files over insecure channels like Slack and email, and never lose an important .env file again. Free for up to 3 teammates.

Zero trust network access — Starter plan free forever: 5 users, 10 remote networks. Replace traditional VPNs with identity-based access to internal resources

Mesh VPN with WireGuard — 6 users, unlimited devices, MagicDNS, exit nodes, subnet routing. Free Personal plan. Best for personal projects and unlimited usage needs.

Find web app vulnerabilities, audit for OWASP Risks

Pareto Cloud is free for up to 5 devices, with no credit card required. The free tier includes the cloud dashboard, alerts to email, Slack and Teams, and the API. Paid Team and Business plans are priced per device per month. The macOS, Linux and Windows apps are open source. Best for open source projects.

Test for modern Internet Standards like IPv6, DNSSEC, HTTPS, DMARC, STARTTLS and DANE