Invio is a free, self-hosted, open-source invoicing application written in TypeScript that lets a user create an invoice, share a secure link, and get paid without requiring the client to create an account.

What it is

Invio is a self-hosted invoicing application distributed as open-source software under the Unlicense, written in TypeScript and published on GitHub by kittendevv and contributors. It sits in the business software and finance/accounting category, and its stated purpose is invoicing "without the bloat": the workflow is to create an invoice, share a link, and get paid. There are no setup wizards and no nested menus to dig through. A public website, a live demo, documentation, and a support channel are linked from the project, and the documentation itself lives in the repository wiki rather than in the README.

The concrete problem Invio addresses is dependence on hosted invoicing SaaS. The README frames this directly: hosting on your own hardware means not having to worry about what happens when a SaaS company changes its pricing or shuts down. The specific thing it replaces is the subscription invoicing service — the paid per-invoice or per-month hosted product — with a self-hosted alternative whose data stays on the operator's own hardware. A second problem it removes is client-side friction: rather than sending an email that prompts "how do I log in?", Invio sends a secure link that needs no account, which removes the account-creation step from the person paying the bill.

Key capabilities

• Create an invoice, share a link, and get paid — the core flow described in the README's "Why Invio?" section.
• Self-hosted deployment, keeping invoice data on the operator's own hardware rather than a vendor's servers.
• Client-facing secure links that require no account, login, or registration for the recipient.
• A dashboard, invoice creation view, settings view, and invoices view, shown as screenshots in the README.
• Free to run with no subscription, no per-invoice charges, and no hidden fees.
• Open source under the Unlicense, so the code can be forked, modified, and self-deployed.
• A hosted live demo and documentation site for evaluating the software before installing it.

Who uses it and how

• Freelancers and small operators who bill clients directly and want the invoice to arrive as a link rather than as an invitation to register for yet another account.
• Self-hosters who run their own hardware and prefer to keep financial records on infrastructure they control.
• Teams that want to avoid ongoing SaaS exposure — the README's stated concern is vendors changing pricing or shutting down entirely.
• Contributors and tinkerers: the project invites forks and pull requests and states that all experience levels are welcome, with bug reports and feature ideas handled through GitHub issues.
• Prospective users evaluating the tool before committing: the README links both a live demo and documentation, so the software can be inspected without a local install.

Getting started

The README's Quick Start section points to the Quick Start guide in the project wiki at github.com/kittendevv/Invio/wiki/Quick-Start. Installation specifics, including any container or package method, are documented there rather than in the README itself.

How it compares

No competing products are named in the facts provided, and no list of paid products that Invio replaces has been supplied, so on the evidence available it stands alone in this registry.

When to use it — and when not to

Choose Invio when the priority is self-hosted invoicing with client-facing links and no account requirement for the payer, and when an Unlicense-licensed, TypeScript codebase that can be forked is acceptable. Be aware that the README is thin on operational detail: installation, deployment, and any backing storage or mail configuration live in the wiki's Quick Start guide, and the README does not state a database, storage backend, or email transport, so a self-hoster must read the documentation before assuming what has to be operated. With 17 open issues and the most recent push on 2026-09-07, the project is active but small, so anyone needing vendor support, SLAs, or a large maintainer team should look elsewhere.