SealTrail

Most audit logs are a lie. They're database rows that anyone with admin access can silently modify or delete. When a SOC 2 auditor asks "how do you prove these logs haven't been altered?", the answer is usually "we trust our DBAs" — which isn't an answer.

SealTrail fixes this with cryptographic hash chains. Each audit event includes a SHA-256 hash computed from the event data, the previous event's hash, and a timestamp. This creates a chain where modifying any single entry breaks every hash that comes after it — making tampering immediately and mathematically detectable.

How it works:

1. Send events to the REST API (actor, action, resource, metadata)
2. SealTrail computes the hash chain automatically
3. Verify integrity at any time — re-walk the chain, recompute hashes
4. If anything was altered, you'll know exactly which event was tampered with

Key features:

- SHA-256 hash chain with canonical JSON serialization
- Chain partitioning for parallel writes at scale
- Atomic writes with conflict detection
- Single-event and full-chain verification endpoints
- TypeScript/JavaScript SDK available on npm
- Free tier: 2,500 events/month

Built for:

- B2B SaaS teams preparing for SOC 2 Type II
- Fintech and healthtech apps with regulatory requirements
- Any application where audit log integrity matters

SealTrail is built with Bun, Hono, and Neon Postgres. The API is hosted in London (Fly.io) for low-latency European access.