Crater

Simple open-source invoicing for small operators

oss-osi-approved stub guide

Overview

Crater is a free invoicing app for freelancers and small businesses. Some micro-sites use it for straightforward membership billing.

At a glance

Field	Value
Categories	`billing-payments`
Deployment	`self-hosted`
License class	oss-osi-approved (`AAL`)
Cost model	`free-self-hosted`
Implementation difficulty	`easy`
Maintenance burden	`medium`
Maturity	`legacy`
Verification	`partially-verified` (2026-07-17)

Cost reality

Free self-host; maintenance risk may dominate.

Pricing and free-tier limits change frequently; re-check official pricing before budget decisions.

Tasks reduced or augmented

Software does not replace community or ops staff. It may reduce or augment:

Basic invoicing
Expense tracking light

Human oversight still needed

Project health
Security updates

Data held

invoices
clients
expenses
Personal data: yes
Payment data: yes / possible

Risks

Area	Notes
Vendor lock-in	Evaluate export formats and API completeness before deep customization.
Security	Apply updates promptly; restrict admin access; enable TLS.
Compliance	Operator remains responsible for privacy and local regulatory obligations.
Licensing	Project activity may be slow—evaluate maintenance risk.
Operational	Plan backups, monitoring, and a restore drill before production use.

Coworking fit

Roles: finance, owner-operator

Workflows: invoice-collections

Problems: automate-billing, reduce-software-cost

Smallest useful experiment

Generate five invoices and a PDF export; assess whether maintenance risk is acceptable.

Typical time to first value: 1–3 days

Implementation guide

See the human-written implementation guide.

Verification

Status: partially-verified
Last reviewed: 2026-07-17
Sources:

Seed entry compiled from official project sites and repositories. Re-verify pricing, license text, and feature claims before production decisions. Star counts and free-tier numeric limits intentionally omitted unless verified at review time.