Desktop accounting workspace · macOS · GPL v3

The day-book, restored.

Own your books. Let AI help.

For the founder-operator who keeps their own books: a desktop accounting workspace that records everything as portable, double-entry Beancount text — a day-book you write, own, and can read a decade from now.

View on GitHub

Apple Silicon · Free forever · No account required

The record proves itself

Every entry, in your own hand

Plain Beancount text. Open in Fava. Validate with bean-check. Leave any time.

main.beancount

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;; main.beancount — Personal Finances;; Maintained by Elena · last reviewed 2026-05-20;; ── May 2026 ──────────────────────────────────────────────────2026-05-02 * "Foundry Labs" "May salary" Income:Salary:Foundry -8,420.00 USD Assets:Checking:Mercury2026-05-03 * "Bridgepoint Property Co." "May rent" Expenses:Rent 2,650.00 USD Assets:Checking:Mercury2026-05-08 * "Whole Foods" "Weekly groceries" #groceries Expenses:Groceries 98.37 USD Liabilities:CreditCard:Amex -98.37 USD2026-05-11 * "Verve Coffee" "Pourover + pastry" Expenses:Coffee 8.25 USD Liabilities:CreditCard:Amex -8.25 USD

Diurnum (dy-UR-num) is a Latin noun meaning account-book, day-book — attested in Juvenal, used in Rome for the running record of daily transactions. Late Latin diurnum became Old French journal; the sense "a daily record of transactions" is first recorded in 1565.

The journal entry — the atom of double-entry bookkeeping — is, etymologically, a diurnum entry. The name is not a metaphor for the product. It is the product, in its oldest form.

dy · UR · num

Messaging pillars

A record that endures

The day-book, restored

Double-entry accounting in its oldest, most durable form. Real P&L and balance sheet — not budget bars. Books, not budgets.

Written in your own hand

Plain Beancount text you own outright. Opens in Fava, validates with bean-check, leaves with you to any plain-text tool.

Every line, accountable

Each figure traces to the entry — and the day — that produced it. AI suggestions are grounded in your ledger and cite their sources.

Built to endure

Local-first, private, version-controlled. A record designed to outlast the software that wrote it. Free and open source, forever.

The diff is the product's soul

Show one on every marketing surface — a real before/after entry says more than any paragraph about transparency and auditability.

2026-05 · main.bean · before / after approval

 ; Stripe payout — 8 May 2026
+2026-05-08 * "Stripe" "Payout"
+  Assets:Bank:Checking      1842.17 USD
+  Expenses:Fees:Stripe        57.83 USD
+  Income:Sales             -1900.00 USD

Diff additions: lapis wash background with lapis-text. Deletions: oxblood wash with oxblood-text. Context lines: muted ink. Monospaced throughout.

Competitive frame

Where Diurnum fits

	Privacy budgeting apps	Cloud SaaS (QBO, Xero)	Raw Beancount + Fava	Diurnum
Job	Track spending	Full accounting	Full accounting, DIY	Full accounting, kept to last
Data	Bespoke local file	Vendor database	Standard text files	Beancount standard
Audience	Privacy-minded consumers	SMBs + accountants	Technical tinkerers	Technical operators
AI	Categorize / import	Black-box automation	None	Grounded, cited, approved
Trust	"Local, trust us"	"Trust us"	"Do it yourself"	"The record proves itself"

Voice

How Diurnum speaks

The learned, composed craftsperson. Precise, literate, calm.

We say "Here is the entry, and the day it was written. Approve it, and the record stands."

We say "Your books are Beancount text. Open them in Fava. Leave any time."

We say "AI proposes. You approve. The day-book records the result."

Never "Supercharge your finances with AI-powered bookkeeping!"

Never "Revolutionize your financial future with cutting-edge automation."

Guardrail: We are a scriptorium, not a Renaissance fair. Classical register lives in proportion, ruled lines, ink, and the serif — not in ornament. One well-placed archival note does the work; never costumed or fussy.