LedgerHashJoin the waitlist
Ledger-as-a-Service

Tamper-evident ledger infrastructure for accounting platforms.

LedgerHash is a hash-linked, append-only journal. Every entry is chained with SHA-256 from a per-tenant GENESIS block, verified at the database, and served over a thin REST API. Your accounting product keeps its UX; we guarantee the integrity of every posting.

Join the waitlistSee the API
SHA-256 hash chainAppend-only at DB levelPer-tenant isolationDeterministic replayREST-only surface

The problem

Accounting backends were not designed to be verifiable.

Most ledgers are a mutable table with a timestamp and good intentions. Rows get edited, balances get patched, and auditors get spreadsheets. There is no cryptographic way to prove a record has not been touched since it was posted.

Silent edits

UPDATE statements on historical rows leave no fingerprint. You can only audit what you remember to log.

Reconciliation drift

Without deterministic replay, running balances diverge from the journal and nobody can tell when it happened.

Weak audit trail

App-level audit logs run on the same infrastructure they are supposed to audit. Auditors have to take your word for it.

What you get

Integrity guarantees you can hand to an auditor.

SHA-256 hash chain

Every journal entry is hashed with its predecessor. Break a link and verification fails at the exact row.

Per-tenant isolation

Writes are scoped by ledger_id. One tenant's chain cannot be rolled into another's.

Deterministic replay

Rehydrate balances from the append-only journal. Same input, same output, always.

API-first

REST-only surface. Thin Lambda router, Postgres functions for writes. Predictable latency, no hidden magic.

How it works

Three calls, one guarantee.

  1. 01

    Post a journal entry

    Your backend calls POST /entries with a canonical payload. Debits and credits must balance or the call fails.

  2. 02

    Chain and persist

    A Postgres function computes SHA-256 over the payload plus the previous entry hash, writes the row, and updates the ledger head.

  3. 03

    Verify any time

    Re-walk the chain from GENESIS and recompute hashes. Any tampering surfaces at the exact row where integrity broke.

Security model

Integrity enforced at two layers.

Postgres triggers block UPDATE and DELETE on journal entries at the database level. On top of that, every entry is linked into a SHA-256 chain rooted at a per-ledger GENESIS block, so even a privileged operator cannot rewrite history without detection.

GENESISsha256#0sha256#1sha256#2sha256#3sha256

Each block commits to the previous block's hash. Recompute from GENESIS at any time to verify the entire ledger.

Developers

A boring API is the point.

REST only. JSON in, JSON out. Timestamps are Unix epoch milliseconds as integers, never ISO strings. Writes go through Postgres functions for atomic chaining. Reads are thin.

curl -X POST https://api.ledgerhash.dev/v1/entries \
  -H "Authorization: Bearer $LEDGERHASH_KEY" \
  -H "X-Ledger-Id: lh_tenant_9f3c" \
  -H "Content-Type: application/json" \
  -d '{
    "external_id": "inv_2026_04_14_0001",
    "occurred_at": 1744588800000,
    "memo": "Invoice 0001 - Acme Ltd",
    "lines": [
      { "account": "1100", "debit":  125000 },
      { "account": "4000", "credit": 125000 }
    ]
  }'
{
  "sequence": 4821,
  "entry_hash":    "b41c...e8",
  "previous_hash": "8f02...a1",
  "ledger_head":   "b41c...e8",
  "recorded_at":   1744588801413
}

Who it is for

Backends, not end users.

Accounting software

Drop LedgerHash behind your existing ledger module. Keep your UI; outsource integrity, retention, and audit evidence.

Fintech backends

Every balance movement becomes a hash-linked journal entry. Deterministic replay makes reconciliation a query, not a support ticket.

Audit & assurance

Give auditors a verifiable, append-only stream. Hash verification replaces trust-me spreadsheets.

Bookkeeping platforms

Protect client books from silent edits. Reversal entries preserve history without forcing your users to relearn anything.

FAQ

Questions we get asked.

Is LedgerHash an accounting app?

No. LedgerHash is ledger infrastructure. Our customers are the backends of accounting software, fintech platforms, bookkeeping tools, and audit products. We do not ship a user-facing ledger UI.

How is immutability enforced?

Two layers. Postgres triggers reject updates and deletes on journal entries at the database level. On top of that, every entry is linked into a SHA-256 hash chain rooted at a per-ledger GENESIS block, so any tampering breaks verification.

What if an entry is posted in error?

Originals are never edited. You post a reversal entry that references the original by id. Both remain in the chain; auditors see the full sequence.

Is there per-tenant isolation?

Yes. Every write is scoped by ledger_id. Hash chains are per-ledger, so tenants cannot influence each other's integrity state.

Is there a sandbox?

Not yet. Sandbox access is opening to waitlist members first — join the waitlist and we'll email you the moment it goes live.

What about HMRC / IRS reporting?

A tax-authority bridge is on the roadmap: LedgerHash becomes the verifiable source of truth behind MTD-style digital links.

Early access

Join the waitlist.

Sandbox access, integration support, and pricing before the public launch. We only email you about LedgerHash.

We only email you about LedgerHash. No marketing lists.