bottomline

An open-source, self-hosted ledger for indie SaaS and side projects. Track every dollar in and out, watch MRR, burn, runway, and net month over month — without shipping your numbers to a third party.

Single-user, single binary's-worth of dependencies, single SQLite file you own.

Features

Multiple projects — each with its own color, entries, recurring rules, and per-project dashboard.
Aggregate dashboard — KPIs across the whole portfolio: Net YTD, MRR, gross burn, net-burn runway, and lifetime totals.
Monthly chart — trailing 12 months of income, expense, and net (composed bars + net line), with a custom paper-card tooltip.
Income & expense breakdowns — twin trailing-12-month category breakdowns showing where the money comes from and where it goes.
Recurring rules — monthly subscriptions and recurring revenue auto-materialize into past entries. Editing a rule propagates field changes (amount, category, type, currency, note) to past entries automatically. A Regenerate button restores entries you deleted manually.
Archive & hard-delete — projects can be archived (hidden from the dashboard, preserved for restore) or permanently deleted (cascades to entries and rules).
Multi-currency — entries in any of 13 supported ISO currencies, aggregated to your base currency at a static FX rate (editable in lib/fx.ts).
Export & import — single-file JSON backup that round-trips losslessly, preserving IDs and foreign keys. curl-able for automated backups.
Custom design system — hand-rolled components, no shadcn/Mantine copy-paste. Bricolage Grotesque + JetBrains Mono on warm paper.
No accounts, no telemetry, no SaaS — your data lives in a SQLite file you own. Run it on localhost, in a Docker container, on a Pi — wherever.

Stack

Layer	Choice	Why
Framework	Next.js 16 (App Router, Server Actions)	First-class server actions for forms; statically-rendered dashboard
Runtime	React 19	`useActionState`, server components
Styling	Tailwind CSS v4	`@theme inline` for hand-rolled tokens, no config file
Language	TypeScript 5, strict	Drizzle gives end-to-end types from DB to UI
DB	SQLite via `better-sqlite3`	Synchronous, fast, zero infra, perfect for single-user
ORM	Drizzle ORM + drizzle-kit	Typed queries, generated migrations
Charts	Recharts	Composable enough to fully restyle
Forms	Native `<form>` + server actions + `useActionState`	No `react-hook-form` needed
Validation	Zod	Shared schemas between form + server action
Dates	date-fns	Tree-shakable, sane API
Package manager	pnpm	Fast, content-addressable

Quickstart

git clone <repo>
cd bottomline
pnpm install
pnpm db:migrate     # creates ./data/bottomline.db
pnpm db:seed        # optional — 2 demo projects, 12 months of activity
pnpm dev

Open http://localhost:3000.

Note: This project uses Next.js 16. params and searchParams are Promises and must be awaited in server components. Tailwind v4 uses @import 'tailwindcss'; in globals.css, not the old @tailwind directives.

Scripts

Script	Purpose
`pnpm dev`	Start the dev server (Turbopack) on port 3000
`pnpm build`	Production build
`pnpm start`	Run the production server
`pnpm lint`	ESLint (flat config)
`pnpm typecheck`	`tsc --noEmit`
`pnpm db:generate`	Generate a new Drizzle migration from `db/schema.ts`
`pnpm db:migrate`	Apply pending migrations to the SQLite file
`pnpm db:seed`	Wipe and reseed with demo data
`pnpm db:studio`	Drizzle Studio (browse the DB in a GUI)

Configuration

Environment

A single env var lives in .env.local:

DATABASE_PATH=./data/bottomline.db

That's it. The data/ directory is gitignored.

In-app settings

Available under Settings:

Setting	Description
Base currency	All aggregates convert into this currency. Default `USD`.
Cash on hand	Used as the numerator in the runway calculation.
Fiscal year start month	For future fiscal-year aggregations.
Categories	Add/rename/delete; income or expense kind, per-category color.
Export & import	Download a JSON backup or replace all data from one.

Concepts

Money

Stored everywhere as amount_cents INTEGER. SQLite's REAL is a 64-bit float and accumulates rounding error on summed financials — so no floats, ever. Display uses Intl.NumberFormat.

Projects

A project groups everything: entries, recurring rules, color, an optional description and launch date.

Archive — sets archived_at. Hidden from the dashboard and aggregates. Restorable from Projects → Archived (or via the project's edit page).
Delete permanently — cascades through entries and recurring rules. Available from the edit page and the archived list. Not undoable.

The slugifier reserves new, archived, edit, settings so a project name can't collide with a route.

Entries

A single table for income and expense (type column). One entry = one transaction. Each has:

A type, amount_cents, currency
A project_id (required)
An optional category_id
An occurred_on date (the canonical date used for monthly bucketing)
An optional note
An optional source_rule_id pointing at the recurring rule that generated it

Recurring rules

Monthly subscriptions, recurring revenue, anything that repeats at a fixed day-of-month. Rules generate entries — they don't replace them. Each rule defines amount, type, currency, category, day-of-month, start date, optional end date.

Auto-materialization

On every dashboard read, the app runs an idempotent materializeRecurring() that inserts any missing entries for active rules.

Forward-only semantics: only months strictly after the latest existing entry for each rule are filled in. This means manually deleting an entry sticks — auto-materialization won't resurrect it.

Editing a rule

When you save a rule edit, the following fields propagate to all materialized entries from that rule:

Field	Propagates?
`type`	yes
`amount_cents`	yes
`currency`	yes
`category_id`	yes
`note`	yes
`day_of_month`	no (would silently rewrite history)
`starts_on`, `ends_on`	no

The save message tells you how many entries were touched ("Saved. Updated 8 past entries to match.").

Regenerate

The Regenerate button on each rule does a full gap-fill — inserts any (rule, month) that's currently missing, including ones you deleted manually or months exposed by extending starts_on backwards. Idempotent.

Deleting a rule

The rule is removed. Past entries are kept — their source_rule_id is set to NULL and they continue to behave like ad-hoc entries from then on.

MRR

Monthly Recurring Revenue, not "monthly income." Computed two ways:

Primary: sum of active recurring income rules' monthly amounts.
Fallback (when a project has no income rules): last full calendar month's income.

The MRR tile caption tells you which one is being shown.

Burn rate

Gross monthly expense — i.e., cash going out, not netted against revenue. Industry-standard definition. Computed as the average over the trailing 3 months.

A €60 domain renewal will spike this by €20/mo for three months even if your steady-state spend is much lower — check the entries table if burn looks off.

Runway

Net-burn-based, the industry-standard definition:

runway = cash on hand ÷ (avg monthly expense − avg monthly income, trailing 3mo)

If net burn ≤ 0 (break-even or profitable), Runway shows ∞ with a green Profitable badge.
Otherwise, months are shown, plus a caption explaining the math: "Cash on hand: €100 · burns €2.95/mo net".

This is the realistic runway. If you want a stress-test of "what if revenue goes to zero tomorrow," divide your cash by the gross Burn tile directly.

Multi-currency

Entries can be in any of the supported currencies. Aggregates convert into your base currency via a static rate table in lib/fx.ts. Editing rates requires editing the file and restarting the server.

Supported: USD, EUR, GBP, CAD, AUD, CHF, JPY, INR, BRL, TRY, MXN, SGD, ZAR.

Future: wire a daily-cached free FX API (e.g. open.er-api.com). For v1 the static table is good enough for a self-hosted single-user app.

Architecture

app/
  layout.tsx                          # Fonts, <TopNav>, footer
  page.tsx                            # Aggregate dashboard
  globals.css                         # @theme inline { ... } design tokens
  loading.tsx, error.tsx, not-found.tsx
  api/
    export/route.ts                   # GET full-DB JSON download
  projects/
    page.tsx                          # List (with ?show=archived toggle)
    new/page.tsx
    [slug]/
      page.tsx                        # Project dashboard
      edit/page.tsx                   # Edit + archive + hard-delete
      entries/page.tsx                # Paginated entries + type filter
      entries/new/page.tsx
      recurring/page.tsx              # Manage rules
      recurring/[id]/edit/page.tsx    # Edit a rule
  settings/
    page.tsx                          # Index
    general/page.tsx                  # Base currency, cash, fiscal year
    categories/page.tsx               # CRUD categories
    data/page.tsx                     # Export + import

components/
  nav/         TopNav, NavLink (active-route logic, client)
  ui/          Button, Card, Field, Input, Select, CurrencyInput,
               SegmentedControl, Tag, EmptyState, Skeleton
  dashboard/   StatTile, Sparkline, MonthlyChart, CategoryBreakdown,
               RunwayBar, ProjectCard
  entries/     EntryRow, EntryTable, EntryForm, EntryFilters,
               RecurringForm
  projects/    ProjectForm, SettingsForm, CategoryEditor,
               ArchivedProjectRow, ImportForm

db/
  schema.ts                           # Drizzle table definitions
  client.ts                           # singleton better-sqlite3 (WAL, FK on)
  migrate.ts                          # tsx-runnable migration runner
  migrations/                         # generated SQL
  seed.ts                             # demo data

lib/
  actions/                            # 'use server' mutations
    projects.ts, entries.ts, recurring.ts,
    categories.ts, settings.ts, data.ts (import)
    _shared.ts                        # ActionState + zod-from-FormData helpers
  queries/                            # server-only typed reads
    projects.ts, entries.ts, materialize.ts
  metrics.ts                          # pure: monthlySeries, mrr*, burnRate,
                                      # netBurnRate, runwayMonths,
                                      # categoryBreakdown, ytdNet,
                                      # lifetimeTotals, monthsToProfitability
  recurring.ts                        # pure: expandRule,
                                      # pendingForwardMaterializations,
                                      # pendingMaterializations
  money.ts                            # cents <-> major, Intl.NumberFormat
  date.ts                             # monthKey, monthsInRange, ranges
  fx.ts                               # static rate table + convert()
  settings.ts                         # KV settings helpers
  slug.ts                             # slugify + reserved-name list
  validators.ts                       # zod schemas shared by forms + actions
  env.ts                              # zod-validated process.env
  cn.ts                               # tiny classname joiner

data/                                 # gitignored
  bottomline.db                       # the database file

Data model

projects            id, slug UNIQUE, name, description, color, launched_on,
                    archived_at, created_at

categories          id, name UNIQUE, kind ('expense'|'income'), color, sort_order

entries             id, project_id FK, type ('income'|'expense'),
                    amount_cents, currency, category_id FK?, occurred_on,
                    note, source_rule_id FK?, created_at
                    -- indexes: (project_id, occurred_on), (type, occurred_on),
                    --          (source_rule_id)

recurring_rules     id, project_id FK, type, amount_cents, currency,
                    category_id FK?, cadence ('monthly'), day_of_month,
                    starts_on, ends_on?, note, active, created_at

settings            key PK, value
                    -- known keys: base_currency, cash_on_hand_cents,
                    --             fiscal_year_start_month

Foreign-key cascades:

Parent	Child	On delete
`projects`	`entries`	`cascade`
`projects`	`recurring_rules`	`cascade`
`categories`	`entries.category_id`	`set null`
`categories`	`recurring_rules.category_id`	`set null`
`recurring_rules`	`entries.source_rule_id`	`set null`

So deleting a project removes its entries and rules. Deleting a category or rule leaves its entries intact and uncategorized / orphaned.

Design system

Fonts

Display / sans: Bricolage Grotesque (variable, latin subset). Confident, humanist, distinctive at large sizes, readable at body sizes.
Mono / numerics: JetBrains Mono. Tabular by default, unambiguous zeros and ones — every number in the UI is in mono with tabular-nums.

Loaded via next/font/google in app/layout.tsx, exposed as --font-display and --font-mono CSS variables.

Palette

A warm-paper ledger feel, no stoplight UI:

Token	Hex	Purpose
`--color-paper`	`#f5efe2`	Page background — warm ivory
`--color-card`	`#fbf7ec`	Card surface, slightly lighter
`--color-ink`	`#1a1714`	Primary text
`--color-muted`	`#6b6357`	Secondary text, axis labels
`--color-hairline`	`#d8cfb8`	1 px borders
`--color-olive`	`#6b6a2a`	Primary accent — buttons, links, focus
`--color-gain`	`#2f6a3a`	Deep moss green — net positive
`--color-loss`	`#a8472b`	Terracotta — net negative

Plus tint/soft variants for backgrounds and an 8-color categorical palette for charts. Defined in app/globals.css under @theme inline { ... }.

Touches

Hairline borders on every surface, 6px rounded corners (not pill, not sharp).
Subtle paper-grain overlay on body::before (pure CSS radial gradients).
Custom focus rings (outline-2 outline-offset-2 outline-olive).
Recharts entirely restyled — dashed horizontal grid, mono ticks, Card-style tooltip, gain-soft and loss-soft gradient bars, ink-color net line.
prefers-reduced-motion guard kills animations.

Export & import

Format

GET /api/export returns a single JSON file:

{
  "version": 1,
  "exportedAt": "2026-05-13T08:58:53.509Z",
  "projects": [ { "id": 3, "slug": "...", ... }, ... ],
  "categories": [ { "id": 1, "name": "Hosting", "kind": "expense", ... }, ... ],
  "recurring_rules": [ ... ],
  "entries": [ ... ],
  "settings": [ { "key": "base_currency", "value": "EUR" }, ... ]
}

Every row, every column, IDs included. Filename is bottomline-YYYY-MM-DD.json.

Automated backup

curl -o "bottomline-$(date +%F).json" http://localhost:3000/api/export

Drop that in cron for daily backups.

Import

Settings → Export & import → Replace all data. Hard-replace semantics:

zod validates the file's shape before touching anything.
Everything happens inside a single SQLite transaction. Partial failure rolls back.
All tables wiped in dependency order; rows reinserted with original IDs so foreign keys stay valid.
sqlite_sequence is bumped to max(id) per table so the next auto-insert doesn't collide.
A browser confirm dialog guards the destructive action.

50 MB file cap — way above any realistic dataset.

Deployment

This is a single-binary-ish Node app. Options in order of simplicity:

Bare metal / Pi / homelab: pnpm build && pnpm start. Run it behind Caddy / nginx / Cloudflare Tunnel. Mount a volume for data/.
Docker: build a standard Node image, copy the project, expose port 3000, volume-mount /app/data. (No Dockerfile shipped — write one if you need it.)
Vercel and friends: not recommended for the default SQLite setup — serverless filesystems are ephemeral. If you must, point DATABASE_PATH at Turso (libSQL) or swap better-sqlite3 for @libsql/client + Drizzle's libSQL driver in db/client.ts.

Back up your DB. This app is self-hosted; nobody else is. Either curl the export endpoint on a schedule (see above) or back up the data/ directory directly.

FAQ

Why is MRR €17 but May's income on the chart is €40? MRR is the recurring part — only active recurring income rules count. A one-off €23 consulting payment shows on the chart but not in MRR.

Why is my Net YTD negative but the mo/mo delta chip is green? The chip shows the change from the prior month. Going from -€30 to -€20 is a +€10 improvement, even though both numbers are losses.

I edited a rule but old entries look the same. Refresh the page — server-component caches revalidate on the action's revalidatePath. If the field doesn't propagate, it's a date field (day_of_month, starts_on, ends_on) — those are intentionally left alone.

I deleted a recurring rule. Where did its past entries go? They're still there in the entries table, just orphaned (their source_rule_id is now NULL). The "↻ recurring" tag disappears because there's no rule to point at.

Can I export to CSV? Not yet. JSON only. Drop a feature request if you need it.

Where do I change the FX rate table? lib/fx.ts. Edit the rates relative to USD and restart the server.

Does dark mode work? No, light only in v1.

License

MIT.

Name		Name	Last commit message	Last commit date
Latest commit History 9 Commits
.github/workflows		.github/workflows
app		app
components		components
db		db
lib		lib
plans		plans
.dockerignore		.dockerignore
.gitignore		.gitignore
AGENTS.md		AGENTS.md
CLAUDE.md		CLAUDE.md
Dockerfile		Dockerfile
README.md		README.md
docker-compose.yml		docker-compose.yml
drizzle.config.ts		drizzle.config.ts
eslint.config.mjs		eslint.config.mjs
next.config.ts		next.config.ts
package.json		package.json
pnpm-lock.yaml		pnpm-lock.yaml
pnpm-workspace.yaml		pnpm-workspace.yaml
postcss.config.mjs		postcss.config.mjs
tsconfig.json		tsconfig.json

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bottomline

Contents

Features

Stack

Quickstart

Scripts

Configuration

Environment

In-app settings

Concepts

Money

Projects

Entries

Recurring rules

Auto-materialization

Editing a rule

Regenerate

Deleting a rule

Categories

MRR

Burn rate

Runway

Multi-currency

Architecture

Data model

Design system

Fonts

Palette

Touches

Export & import

Format

Automated backup

Import

Deployment

FAQ

License

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