Till Death Do Us Parse
Designing an API Style for the Messiest Documents on Earth
What is INHERIT?
The open data standard for estate planning — structured, validated, and jurisdiction-aware.
INHERIT stands for INterchange format for HERITance data. It is an open data standard that gives wills, trusts, powers of attorney, and related estate information a shared digital format.
Estate data is one of the last unstructured frontiers. When someone dies, executors make dozens of phone calls because systems cannot share data. Wills arrive as PDFs. Asset lists live in spreadsheets. Tax calculations sit in separate tools. Nothing connects.
INHERIT provides the missing data layer. Built on JSON Schema Draft 2020-12 and OpenAPI 3.1, it gives estate data one structured format that validates automatically — across 21 jurisdictions and 7 legal traditions, from IHT nil-rate bands to Islamic forced heirship.
It is not another FHIR-style standard. FHIR is healthcare; INHERIT is purpose-built for wills, assets, bequests and cross-jurisdiction rules. We learned from FHIR's complexity and kept ours deliberately lightweight.
Automatic validation
Level 1 (structural) then Level 2 (referential integrity) — in under 300ms. The same document always produces the same result.
21 jurisdictions
Singapore, Japan, Australia, India, China, US, UK, and more. Each jurisdiction captures local tax rules, court procedures, and succession law.
Privacy by design
The schema itself stores no personal data unless you choose to. All sensitive processing stays ephemeral and under user control. Built for GDPR and PDPA.
How it started
From model trains to open data standards.
Richard Davies spent 25 years running a secondhand retail company. Over and over, the same thing happened: a man would pass away, and his wife would come in with boxes of model trains, vinyl records, or camera equipment — collections that meant everything to him and nothing to the people left behind.
The data about those assets — what they were, what they were worth, who should get them — was scattered across handwritten notes, old spreadsheets, and half-remembered conversations. There was no structured way to capture it, no standard format to pass it on.
That pattern repeated across every category of estate data: wills, property, pensions, insurance, digital accounts. The problem was always the same. Estate data has no shape.
INHERIT gives it one.
Follow along
Links from the slides — open any page while you watch.
Live demo
See INHERIT in action — from scanned document to structured, validated estate data.
WillScan.ai
Upload a will, get structured INHERIT JSON. AI-powered document extraction that turns paper wills into validated, machine-readable data.
Try WillScan.ai ↗INHERIT Companion
Merge two estate documents when life changes. See what happens when Mark from Bristol marries Katrina from Singapore and English law revokes his will.
Open the Companion ↗Under the hood
What API developers ask about INHERIT — and the answers.
How does the validator work?
JSON Schema 2020-12 with custom referential integrity rules. Paste a document, it runs Level 1 (structural) then Level 2 (all IDs actually exist) in under 300ms. The public validator on dev.openinherit.org is the exact same engine we use internally.
How do extensions work without breaking existing documents?
Every extension lives in its own x-inherit- block and is versioned with semver. A document can carry 0–30 extensions at once and still validate cleanly. The core schema stays stable.
What does the SDK look like?
One line in TypeScript: const estate = new Estate(json); await estate.validate(); — full type safety, auto-complete, and the same validation engine as the website.
Can I use this in my own product?
Yes. Everything is Apache 2.0. You can start building against the public validator and schema reference on openinherit.org right now. No registration, no fees.
How do you handle non-Western family structures?
Through the x-inherit- extension system plus the entity-map document. Polygamous families, Islamic forced heirship, Hindu joint family property — jurisdiction- and faith-specific rules live in their own extensions while the core schema stays clean.
What about GDPR and data privacy?
The schema itself is just structure — no personal data is stored in INHERIT documents unless the user chooses to. Sensitivity markers, redaction support, and data classification at the field level. All sensitive processing stays ephemeral and under user control.
What’s the adoption story?
Testate’s own products — WillScan.ai is already live, MyFamilyInherits and LegacyLists launching soon — are the first adopters. We’re staying private until we have production support ready, then opening everything.
Are you planning digital signing or e-wills?
Yes — it’s on the roadmap in the execution and integrity sections. We’re watching jurisdictions that have already legalised electronic wills (including Singapore) so we can add the fields as soon as they’re needed.
How can I get involved?
Try the validator today, then get in touch. We’re especially looking for people who want to build the next jurisdiction or faith extension.
Built with experts
INHERIT is shaped by people who understand both standards and the real world.
Juan Cruz Viotti
Validation Technology Partner · Sourcemeta
Author of “Unifying Business, Data, and Code: Designing Data Products with JSON Schema” and founder of Sourcemeta. Juan provides the industrial-strength JSON Schema validation engine that powers INHERIT.
Open source, open governance
Apache 2.0 · Steering committee forming
The INHERIT standard lives at github.com/openinherit/standard. The repository will become public once we have a steering committee in place. We want to get governance right before we open the gates.
Get involved
INHERIT needs domain experts in every jurisdiction. Here’s how to contribute.
Jurisdiction partners needed
We’re looking for succession law, tax, and faith experts in each of our 21 jurisdictions — including Singapore. Help us get the rules right for your region.
See all extensions →Developer portal
Schema reference, SDKs, validator, getting started guides. Everything you need to build with INHERIT.
dev.openinherit.org ↗Try the validator
Paste an INHERIT document and see two-level validation in real time. The fastest way to understand the standard.
Open the validator ↗Let’s connect
I’ll be at the event on both days — Tuesday 14 April and Wednesday 15 April — so come and say hello. I have business cards and flyers with everything you need to get started with INHERIT.
At the venue? Pick up a business card or flyer at the front after my talk on Stage 2.