Pare

Lean, sovereign bookkeeping and invoicing for Swedish companies. Double-entry on the BAS chart of accounts, moms (incl. förvärvsmoms), SIE 4E import/export, and an MCP so an AI assistant can run the books without ever seeing who the counterparties are.

Built by Bright Interaction, first for our own books, open-core. Live at pare.brightinteraction.com.

Why

Fortnox, Visma and Bokio get expensive fast once you use them properly and want to automate, and their APIs fight you. Pare is the honest minimum that replaces them for a service company's own books and hands the accountant a valid SIE file at year-end.

Privacy model (two layers)

1. At rest: counterparty identities and PII (name, org-nr, personnummer, IBAN, address, email) are encrypted with envelope AES-256-GCM. A per-company data key (DEK) is wrapped by the master key (PARE_MASTER_KEY); a key_id fingerprint on each company makes future rotation possible. Amounts, account codes and dates stay in clear so the ledger is queryable. A database dump leaks no identities.
2. At the MCP/LLM boundary: Shield tokenizes identities before anything reaches the model (Kund#A3F2, never the real name). Amounts stay visible so the assistant can categorize, reconcile and prepare the momsrapport. A CI completeness guard fails the build if a PII field is left untagged.

Features

• Double-entry ledger on the BAS 2025/26 chart; verifikat are DB-immutable, corrections are reversing entries (rättelseverifikat).
• Invoicing: draft -> finalize (auto-posts a balanced verifikat) -> PDF; gap-free per-year numbering; multi-currency; kreditfaktura (credit notes) + refunds.
• Payments: settle an invoice with automatic account assignment (1510/2440), currency difference (3960/7960), öresavrundning (3740); partial payments; a smart match from an incoming amount to the right open invoice.
• Leverantörsfaktura (AP) with förvärvsmoms self-assessment on foreign services.
• Moms: full momsdeklaration boxes (rutor), period-scoped.
• SIE 4 import (with #IB opening balances) and export (with #IB/#UB/#RES).
• Bank reconciliation: import a camt.053 or CSV statement, auto-match credits to open invoices, one-click book (or categorize to any account). The payer text is encrypted at rest and never crosses the AI boundary.
• Receipts/underlag: encrypted document capture attached to supplier invoices.
• Reports: resultat- + balansräkning (period-correct), momsdeklaration, huvudbok, verifikationslista, reskontra (aged receivables + payables), CSV.
• Year-end close (bokslut) with first-class fiscal years + period lock.
• Trust: period lock, audit log with an HMAC hash chain (tamper-evident), undo, read-only accountant (revisor) role.
• Email: send invoices + payment reminders over SMTP (optional).
• MCP: composite read tools + write tools with a per-write ceiling and dry_run.

Configuration (PARE_*)

Var	Required	Purpose
PARE_DATABASE_URL	yes	Postgres DSN
PARE_MASTER_KEY	yes	32 bytes base64; wraps per-company DEKs
PARE_SHIELD_KEY	for MCP	32 bytes base64; MCP tokenization vault
PARE_MCP_KEY	for MCP	org key gating /mcp (min 16 chars)
PARE_MCP_MAX_ORE	no	per-AI-write ceiling in öre (default 50 000 000)
PARE_GOTENBERG_URL	no	PDF renderer (default http://gotenberg:3000)
PARE_SMTP_HOST/PORT/USER/PASS/FROM/FROM_NAME/TLS	no	email (no-op if unset)
FLARE_DSN	no	error reporting to a Sentry-compatible sink
PARE_INSECURE_COOKIES	no	1 disables Secure cookies for local HTTP dev

See .env.example for the full list with comments, including the next-step integration placeholders (PSD2 bank feed, Mollie payment gateway). The live config status (email/MCP/Flare on or off) is shown on the in-app /api page.

API (MCP)

JSON-RPC 2.0 over POST /mcp, org-key auth in the Authorization header. Read tools: pare_financial_overview, pare_unpaid_invoices, pare_trial_balance (period), pare_moms_report (period), pare_export_sie, pare_recent_activity, pare_match_payment. Write tools (ceiling + dry_run): pare_post_verification, pare_record_payment. Every counterparty identity in a response is Shield- tokenized. The live, always-accurate tool list is on the in-app /api page.

Integrations

SIE 4 (Fortnox/Visma/accountant), Gotenberg (PDF), SMTP (Resend/SES), Flare (errors), and the MCP (Claude).

Layout

• internal/crypto envelope encryption (at rest)
• internal/ledger double-entry engine, BAS classification, reports/statements
• internal/moms VAT engine (output, input, förvärvsmoms, momsdeklaration)
• internal/sie SIE 4 read/write (CP437)
• internal/invoice invoice model -> verifikat lines
• internal/store persistence (sqlc), all business logic
• internal/shield MCP-boundary tokenization
• internal/mcp the pare MCP server
• internal/email SMTP mailer
• internal/handler chi router + server-rendered operator UI
• internal/render gotenberg PDF client + invoice template
• internal/config, internal/db (goose migrations + sqlc), cmd/server

Build, test, run

go build ./...
# tests need a Postgres:  PARE_TEST_DATABASE_URL=postgres://... go test ./...

To self-host, copy .env.example to .env, fill PARE_MASTER_KEY (and the MCP keys if you want the AI assistant), then docker compose -f deploy/docker-compose.yml up -d and open http://localhost:8080. Migrations run on boot (goose); SyncChart backfills chart additions.

License

Fair-code under the Pare Sustainable Use License (see LICENSE and LICENSING.md): self-host and use it freely, even to keep your clients' books, but you can't resell it as a hosted service. A private pro build overlay (Go build tag pro) is held back for multi-company, bank feeds, Peppol, payroll and the hosted SaaS.