Redmine vs Slack: Complete Comparison (2026)
An in-depth comparison of Redmine and Slack to help you choose the right tool for your business.
Last updated: November 2026
Redmine
6.3/10
Free, open-source, self-hosted web application for issue tracking and multi-project management, with Gantt charts, wikis and time tracking, aimed at technical teams.
Slack
7.1/10
Slack is a channel-based messaging platform from Salesforce, with Lists, canvases, huddles and Workflow Builder for team coordination and light task tracking.
Feature-by-Feature Comparison
| Feature | | |
|---|---|---|
| Scores | ||
| Overall Rating | 6.3/10 | 7.1/10 |
| Cost | 10/10 | 5/10 |
| Ease of Use | 4/10 | 7/10 |
| Analytics | 4/10 | 3/10 |
| Customization | 9/10 | 7/10 |
| Scalability | 5/10 | 9/10 |
| Support | 3/10 | 6/10 |
| Integration | 6/10 | 10/10 |
| Security | 6/10 | 9/10 |
| Pricing | ||
| Free plan | Yes | Yes |
| Cheapest paid plan | Contact for pricing | €8/user/mo Pro |
| Estimated cost for 10 users | Free Open source (self-hosted) | Free Free |
| Features | ||
| Gantt charts | ||
| Time tracking | ||
| App integrations | ||
| Collaboration tools | ||
| Docs | ||
| File sharing | ||
| Task lists | ||
| Task management | ||
| Client collaboration | Not listed | |
| Kanban boards | Not listed | |
| Knowledge base | Not listed | |
| Reporting | Not listed | |
| Scheduling | Not listed | |
| Spreadsheet interface | Not listed | |
| Team messaging | Not listed | |
| Timeline view | Not listed | |
| Workflow automation | Not listed | |
Redmine vs Slack cost by team size
| Team size | Redmine | Slack |
|---|---|---|
| 1 user | FreeOpen source (self-hosted) | FreeFree |
| 5 users | FreeOpen source (self-hosted) | FreeFree |
| 10 users | FreeOpen source (self-hosted) | FreeFree |
| 25 users | FreeOpen source (self-hosted) | FreeFree |
| 50 users | FreeOpen source (self-hosted) | FreeFree |
The plan that fits each team size, billed monthly, before add-ons and usage charges. Each cost opens that tool's pricing calculator for the team size.
Which One Should You Choose?
Why choose Redmine
- Higher Cost score (10/10 vs 5/10)
- Higher Customization score (9/10 vs 7/10)
- Better fit for developers (9/10 vs 7/10)
- Includes Gantt charts, which Slack lacks
- Includes Time tracking, which Slack lacks
Why choose Slack
- Higher Scalability score (9/10 vs 5/10)
- Higher Integration score (10/10 vs 6/10)
- Better fit for enterprise (9/10 vs 5/10)
- Better fit for small business (8/10 vs 6/10)
Pros & Cons
Redmine
Pros
- No licence fees under GPL v2, so the only costs are hosting and administration.
- Trackers, workflows and custom fields on issues, projects, users and time entries can all be configured in depth.
- Built-in Gantt chart, calendar, time tracking, and per-project wiki and forums cover many needs without plugins.
- Native integration with Git, Subversion, Mercurial, Bazaar and CVS suits software teams.
- The REST API in JSON and XML, with API-key authentication, supports automation.
Cons
- Reviewers widely describe the interface as dated.
- Agile boards and Kanban need third-party plugins and configuration.
- Reviewers report that it becomes slow on big or complex projects.
- Self-hosting needs Ruby on Rails skills, and there is no official vendor support.
- Advanced analytics need plugins, and some commercial plugins cost roughly $99 to $499.
Slack
Pros
- The app ecosystem is very large, and tools such as ClickUp, Notion, HubSpot and Clockify can post updates into channels.
- Slack Connect lets teams work in shared channels with up to 250 outside organizations on paid plans.
- Compliance coverage is broad, including ISO 27001, SOC 2 Type II, FedRAMP Moderate and HIPAA configurability.
- Lists add table and board layouts with assignees, due dates and subtasks, without leaving chat.
- Workflow Builder automates routine requests and approvals without code.
Cons
- There are no native Gantt charts, dependencies, time tracking or portfolio reporting, so Slack doesn't replace a dedicated PM tool.
- Frequent notifications and busy channels can interrupt focus, a common complaint in reviews.
- The free plan keeps only 90 days of message history and allows 10 apps.
- Advanced AI features require Business+ or above, and per-user costs add up as teams grow.
- Reviewers report that finding older messages through search can be difficult.
Not sold on either?
Frequently Asked Questions
Slack scores higher on our Project Management criteria: 7.1/10 against 6.3/10 for Redmine. The largest gap is in Cost: 10/10 for Redmine and 5/10 for Slack.
Yes, both Redmine and Slack have a free plan.
Slack is the better fit for enterprise: we rate it 9/10 for them, against 5/10 for Redmine.
Redmine has Gantt charts and Time tracking, which Slack lacks.
