Open Source Gantt Chart

A gantt chart is built around time, dependency, and sequencing. It shows when work starts, when it should finish, and which tasks block others. A kanban board is better for flow and prioritization, while a task list is better for simple ownership. If dates, lead times, milestones, and critical path decisions drive the project, a gantt chart is the right planning view.

The license may allow free use, but the real cost depends on hosting, support, backups, upgrades, and training. Some tools are simple desktop applications with almost no operating cost. Others are web applications that need a database, authentication, monitoring, and someone responsible for maintenance. Also check whether any companion services, mobile apps, or enterprise features are under a different license.

Use a desktop gantt chart when one planner owns the schedule, offline work matters, and file based exchange is acceptable. Use a web based tool when multiple people need to update progress, comment, or view the plan without passing files around. The web option usually gives better permissions and audit history, but it also introduces hosting, access control, and upgrade responsibilities.

MPP import is often imperfect because commercial project files contain scheduling rules, calendars, custom fields, resource settings, and constraints that may not map cleanly. Expect task names and dates to come across more reliably than baselines, formulas, earned value fields, or complex resource assignments. Always test with a real file, then compare dependencies, durations, milestone dates, and calendar exceptions before trusting the migrated schedule.

Look for exports that preserve structure, not just a picture of the chart. CSV is useful for task lists, but it may lose dependencies, hierarchy, calendars, and baselines. Project exchange formats are better when another planner must continue editing the schedule. PDF or image export is useful for reporting only. If the tool has an API or documented database schema, that can be the most reliable exit path.

Some do, and some only approximate scheduling. Check support for finish to start, start to start, finish to finish, lag, lead time, constraints, and milestone behavior. Then change one upstream task and confirm downstream dates move as expected. Critical path is only useful if calendars, task durations, and dependency logic are consistent. A pretty chart with manual dates can hide schedule risk.

First decide whether you need simple assignees or real resource leveling. Simple assignment shows who owns a task. Resource planning should account for availability, capacity, nonworking days, allocation percentage, and overbooking. For construction, manufacturing, agencies, and internal platform work, resource conflicts can matter as much as task sequence. Test the tool with shared people or equipment across overlapping tasks.

A shared gantt chart needs more than a public view link. Look for roles that separate schedule editors, task contributors, clients, and read only stakeholders. Good controls include change history, comments tied to tasks, notifications, and protection against accidental edits to approved dates. If many users update progress, auditability matters because one small date change can affect the whole project plan.

Baselines are important when you need to measure variance from an approved plan. Without them, each schedule update overwrites the evidence of slippage or recovery. A useful baseline feature should capture planned start, planned finish, duration, and milestone dates, then show differences against the current schedule. For contractual work, steering meetings, or postmortems, baselines are often more valuable than extra chart styling options.

Integrations vary from simple imports to two way synchronization. A calendar feed may show milestones but not dependency logic. An issue tracker integration may map issues to tasks, but status, estimates, and hierarchy often need cleanup. Be careful with two way sync because conflicting edits can corrupt dates or ownership. For serious use, prefer a documented API, webhook support, or a clear one way source of truth.

Ask how authentication works, whether single sign-on is supported, how permissions are enforced, and where uploaded files or attachments are stored. Project schedules can expose staffing plans, delivery dates, customer names, and vendor dependencies, so they are not harmless documents. Also check backup encryption, update process, audit logs, and whether administrators can review access without reading every project plan.

Offline support depends heavily on the architecture. Desktop tools usually work offline by default, while web based tools may require a network connection unless they have explicit offline caching. Mobile support is often better for viewing than editing because drag based scheduling is awkward on small screens. If field updates matter, test progress entry, comments, and attachment uploads from the actual phones your team uses.

Large schedules stress both the scheduler and the user interface. Thousands of tasks, deep hierarchies, many dependencies, and resource calculations can slow down recalculation and rendering. Browser based charts may struggle before the database does. Test with a realistic project size, including completed tasks and historical baselines. Also check filtering, collapsing groups, and search, because performance is only useful if planners can still navigate the schedule.

Back up the database, uploaded files, configuration, and any custom plugins or templates together. A database dump alone may not restore attachments, avatars, generated reports, or integration settings. Schedule automated backups, test restores, and keep copies outside the host running the application. For file based desktop tools, store project files in a versioned location so accidental edits or corrupted files can be rolled back.

Your risk depends on the data format and deployment complexity. If projects live in plain files or can be exported with dependencies and calendars intact, switching is manageable. If the tool stores schedules in a custom database with weak export, abandonment becomes harder. Before adopting, confirm you can run the current release without outside services, archive installers or containers, and export a complete project on demand.