The whole model on one page.

Core concepts

curl https://api.ledgerpost.dev/v1/entries \
  -H "Authorization: Bearer $LEDGERPOST_KEY" \
  -H "Idempotency-Key: 9f2c-entry-4471" \
  -d '{
    "description": "invoice 4471 paid",
    "postings": [
      { "account": "cash",             "amount":  4500, "side": "debit"  },
      { "account": "accounts_receivable", "amount": 4500, "side": "credit" }
    ]
  }'

{
  "id": "ent_5Kd91",
  "sequence": 88214,
  "committed_at": "2026-07-21T18:04:11Z",
  "hash": "b7…e0",
  "previous_hash": "a1…9c"
}

Official SDKs wrap the API, handle idempotency keys, and verify the proof on reads for you.

npm install @ledgerpost/client

import { Ledgerpost } from "@ledgerpost/client";
const lp = new Ledgerpost(process.env.LEDGERPOST_KEY);

await lp.entries.commit({
  idempotencyKey: "9f2c-entry-4471",
  description: "invoice 4471 paid",
  postings: [
    { account: "cash", amount: 4500, side: "debit" },
    { account: "accounts_receivable", amount: 4500, side: "credit" },
  ],
});

Your service posts an entry. Ledgerpost validates that it balances, appends it to the log, links it to the hash of the previous entry, and commits. Reads return the entry with its proof; webhooks fan the entry out to whatever you build downstream.