The best free open source tools: Business & clients (2026)

The open source CRM you shape to your business: custom objects, kanban pipelines, workflows, synced email and calendar, AI agents. Replaces Salesforce and the CRM side of HubSpot, without paying per user.

Replaces:Salesforce,HubSpotSaves €25/month

Your booking link on your own domain: slots, Google Calendar, meeting link created automatically. Calendly caps you at one event type on the free plan; this one has no limits.

Replaces:Calendly,Cal.comSaves €12/month

Your forms and surveys, hosted at home, with no response cap. Typeform shuts the tap at 100 responses a month; here there is no tap.

Replaces:Typeform,TallySaves €35/month

Customer support in one place: email, live chat on your website and WhatsApp in a single inbox, with a help center and an AI assistant. Free, with no per agent pricing, on your own server.

Replaces:IntercomSaves €25/month

The business-app builder you host yourself: plug in a spreadsheet, a database or an API, draw screens and forms, add automations. Free on your server, with no user limit.

Replaces:Glide,Softr,RetoolSaves €22/month

The open source DocuSign-style e-signature: you drop a PDF, place the fields, send it, people sign from their phone. Unlimited templates and sends, on your server.

Replaces:DocuSignSaves €9/month

The open source alternative to Jira, Linear and Monday. You put Plane on your own server and run your projects, sprints, docs and incoming requests, without paying per head.

Replaces:Jira,Linear,MondaySaves €9/month

The open source newsletter manager: lists, subscribers, campaigns and transactional emails, on your server. No contact cap, no paid version, and you send through the service of your choice.

Replaces:Brevo,MailchimpSaves €7/month

The open source ERP that replaces Sage: accounting, invoicing, purchasing, sales, stock, manufacturing, projects and CRM in one tool. Free on your own server, with no per user licence, and a French extension for the FEC and VAT.

Replaces:SageSaves €38/month

The open source Typeform-style form builder, one question at a time, hosted on your own server. Surveys, quizzes, contact forms, payments: your answers stay in your database, with no cap.

Replaces:Typeform,TallySaves €35/month

The open source email platform: newsletters, automations and transactional emails from one dashboard, at your place. Unlimited contacts, sending through Amazon SES for a few cents per thousand.

Replaces:Mailchimp,BrevoSaves €12/month

The open source alternative to Trello: boards, lists, cards, labels, checklists, due dates and a calendar view. Your Trello boards import in a few clicks, and on your own server your whole team uses it for free.

Replaces:TrelloSaves €6/month