pytm vs ThreatModeler Nexus

pytm is a free, open-source Python framework for creating threat models from architectural descriptions. A model is defined in Python with elements such as servers, data stores, actors, processes, data flows, and trust boundaries. From it, pytm can generate data flow diagrams, sequence diagrams, and relevant threats. Templates can produce reports with diagrams and findings, and a RevealMD template can create slides for browser presentation. Data flow diagrams use Graphviz DOT, while sequence diagrams use PlantUML. Models can be imported from JSON with pytm's Python load function. Users can supply a custom threats file and change finding attributes such as CVSS score, response text, and severity. Requirements include Python 3.11 or later, Graphviz, Java OpenJDK 10 or 11, and plantuml.jar; Linux and macOS are listed, while Windows use is documented through Devbox in WSL. The project also documents container and Devbox dependency workflows. The README warns that strings in threats.json are evaluated with eval(), so the file's permissions need protection against unauthorized changes.

ThreatModeler Nexus is an agentic platform for secure design and governed threat modeling across applications, cloud and hybrid architectures, devices, and operational technology. Its Secure Design Graph connects architectures, threats, controls, compliance requirements, and security decisions. System Mapping, Graph, and Reporting agents operate on that graph. Supported methods include STRIDE, PASTA, and CSA MAESTRO for agentic systems, and findings map to more than 180 regulatory and security frameworks, including NIST, ISO 27001, PCI DSS, HIPAA, DORA, and the EU AI Act. A built-in MCP Server checks pull requests and commits against the current threat model and returns threats, requirements, and mitigations in developer workflows. Integrations include infrastructure tools, cloud providers, code platforms, ServiceNow, and ArmorCode. Customers can connect their own AI model, with a deterministic framework governing output. Web, API, and self-hosted environments are listed. A free Community Edition is available; the ThreatModeler license costs $4,000 a year on a 12-month contract. Additional AWS infrastructure costs may apply.