What is LINE Harness used for?

LINE Harness is a self-hosted, open-source CRM for LINE Official Accounts with step messaging, broadcasts, forms, reservations, an MCP server and a TypeScript SDK. It is a good fit for marketing automation for LINE Official Accounts and customer follow-up sequences on LINE.

Is LINE Harness open source?

Yes. LINE Harness is open source under the MIT licence. Its source code is on GitHub at Shudesu/line-harness-oss and is written mainly in TypeScript.

Is LINE Harness free?

Yes. LINE Harness is open source, so the software itself is free to use. A managed cloud version is also available.

Can I self-host LINE Harness?

Yes. LINE Harness can be self-hosted on your own server or infrastructure.

What is LINE Harness an alternative to?

LINE Harness is an open-source alternative to LINE and Kommo. Other open-source alternatives to LINE include Signal Desktop, Session and Telegram Desktop.

Is LINE Harness actively maintained?

Yes. The most recent commit to LINE Harness was on 11 September 2026, and the latest release is v0.24.1, published on 11 September 2026. The project has 596 stars on GitHub.

LINE Harness: open-source alternative to LINE, Kommo

About LINE Harness

L Harness is an open-source CRM for LINE Official Accounts, aimed at Japanese businesses that use LINE to talk to customers. The README presents it as a free alternative to paid LINE marketing tools, with step messaging, broadcasts, segment delivery, rich menu switching, forms and reservations. It is built with TypeScript on Cloudflare Workers and D1 and can be operated from Claude Code through MCP, and a TypeScript SDK is provided.

The README states that the software itself carries no usage fee, while LINE Official Account message charges, Cloudflare plans and usage, a custom domain, setup and maintenance, and any external AI service are separate costs, and it notes that the free Cloudflare D1 plan errors out when daily limits are reached. A plugin marketplace in beta lets developers extend delivery rules, automation and integrations from separate repositories and Workers so product updates do not overwrite custom code, though API compatibility still needs testing.

The project was renamed L Harness in August 2026 while keeping the old repository URL and package identifiers for compatibility. It is licensed under MIT, with an official managed L Harness Cloud offered separately, a wiki and a video walkthrough. The README is primarily in Japanese.

Key features

Step messaging and broadcasts for LINE
Segment delivery and rich menu switching
Forms and reservations
MCP server and TypeScript SDK
Runs on Cloudflare Workers and D1
Plugin marketplace in beta

Good fit for

→Marketing automation for LINE Official Accounts
→Customer follow-up sequences on LINE

Built with: TypeScript
Tags: line; crm; marketing-automation; cloudflare-workers; mcp; self-hosted; japan; typescript

LINE Harness: questions and answers

What is LINE Harness used for?: LINE Harness is a self-hosted, open-source CRM for LINE Official Accounts with step messaging, broadcasts, forms, reservations, an MCP server and a TypeScript SDK. It is a good fit for marketing automation for LINE Official Accounts and customer follow-up sequences on LINE.
Is LINE Harness open source?: Yes. LINE Harness is open source under the MIT licence. Its source code is on GitHub at Shudesu/line-harness-oss and is written mainly in TypeScript.
Is LINE Harness free?: Yes. LINE Harness is open source, so the software itself is free to use. A managed cloud version is also available.
Can I self-host LINE Harness?: Yes. LINE Harness can be self-hosted on your own server or infrastructure.
What is LINE Harness an alternative to?: LINE Harness is an open-source alternative to LINE and Kommo. Other open-source alternatives to LINE include Signal Desktop, Session and Telegram Desktop.
Is LINE Harness actively maintained?: Yes. The most recent commit to LINE Harness was on 11 September 2026, and the latest release is v0.24.1, published on 11 September 2026. The project has 596 stars on GitHub.