Guard License Server — Offline-First Software Licensing

The challenge

Software vendors need licenses that are hard to fake or copy, work when the license server is down, and can be locked to one machine or shared (floating) between machines.

Approach

Licenses signed with Ed25519; apps verify locally without calling the server. Machine binding via CPU, MAC address, disk, and hostname. Offline grace period when the server is unreachable. Admin API with rate limits and structured logs. Client SDK compiled with Nuitka to resist reverse engineering. Built with Python, FastAPI, PostgreSQL, SQLite, MessagePack, AES-256-GCM, Docker, Loguru.

Results

• Digitally signed licenses — hard to fake or copy.
• Node-locked and floating license models.
• Offline grace period during license-server outages.
• AES-256-GCM encrypted storage backends.

Metrics

Technologies

• Python
• FastAPI
• PostgreSQL
• SQLite
• MessagePack
• AES-256-GCM
• Ed25519
• Docker
• Loguru
• Nuitka