The battle tested workflow engine for serious software
Enterprise-level starter kit, a full workflow engine for process-driven applications and a complete audit trail with built-in GDPR-safe erasure - Halley was built for the serious stuff.
No spam — we'll email you when Halley is ready to try.
Every change saved automatically, guaranteed
Halley appends every change automatically before anything happens. Your application responds to the change after it's been saved ensuring your history is complete. this becomes your immutable source of truth.
The superpower to replay data from any point in time
Since you now have a full timeline of all data changes, you can replay the events to see exactly what the state of the world was as it was at any point in time.
See the full story of anything and answer exactly what happened
The timeline UI shows every state transition as it happened. No more digging through logs. Ever.
GDPR Right-to-erasure without breaking your history
Immutable event logs and GDPR's Article 17 don't normally get on very well — you can't delete an event without breaking the history it belongs to. Halley solves this with crypto-shredding, the same pattern used in many healthtech systems.
Get the pluginMark PII once, encrypt it everywhere
Tag personal data on your events with a decorator. Everyone gets their own encryption key, and PII is encrypted field-by-field before it ever leaves your application.
Erase the key, keep the history
An erasure request deletes the person's key — nothing else. On replay their PII renders as [DELETED], while every event, timestamp and state transition stays intact.
Built for software that needs to be auditable and transparent
Anywhere that simple CRUD doesn't cut it any more, this is probably the setup and toolset you've been looking for.
Battle-tested patterns
Halley provides real-world, production-proven architecture. You'll even get your own internal ops tool to help manage all your data.
For process-heavy products, not simple CRUD
If your product is really a set of long-running processes — onboarding, assessments, approvals — Halley gives you the architecture to match.
Compliance as architecture, not an afterthought
Audit trails, complete history and Article 17 erasure are built into the foundations, so you're not bolting them on the week before a compliance review.
Frequently asked questions
The things people usually want to know before joining the waitlist. Anything else, ask on GitHub.
Fancy skipping the hard bit?
Join the waitlist and we'll email you when Halley is ready to try. No spam — just the one email that matters.