Open Source Ticketing Platforms
Ticketing software with published source code, compared by licence and how you can run it
Open source software publishes its source code, the human-readable instructions a program is built from. For an event organiser this means you, or someone you hire, can read how the platform works, change it, and run your own copy without asking the original maker.
Publishing code is not one single promise. The licence sets what you may do with the code, whether the hosted service runs that same published code, and whether self-hosting is free. This guide groups the providers reviewed on this site by those questions.
This is a list of the providers with detailed comparisons here, not a directory of every open source ticketing project.
Chobble Tickets is open source
The complete Chobble Tickets product is published under AGPL-3.0-only, a copyleft licence. Copyleft means anyone can read, change and run the code, and a business that runs a changed version as a service must publish its changes under the same licence.
There is no hosted-only feature tier and no separate charge to self-host. The managed service at £50/year or £5/month runs the same source-published product, with no per-ticket platform fee.
Open source and source-available providers reviewed here
Each provider below publishes source code, but under different licences and with different conditions. The table records the licence, whether the hosted service runs the published code, and the main qualification.
| Provider | Licence | Hosted service runs the published code? | Main qualification |
|---|---|---|---|
| Chobble Tickets | AGPL-3.0-only (copyleft) | Yes, the same product | £50/year or £5/month managed, or self-host with no Chobble fee, and no per-ticket platform fee. |
| Hi.Events | AGPL-3.0 with attribution terms | Yes | Free self-hosting shows a "Powered by" link; a commercial licence removes it. The hosted plan charges per paid ticket. |
| Pretix | AGPLv3 core | Core yes; enterprise plugins proprietary | The Community edition is free to self-host; some enterprise features are sold as closed plugins. The hosted plan charges a percentage per ticket. |
| Revel | MIT (permissive) | Yes, the same product | A permissive licence lets anyone use, change, rebrand or resell the code. The hosted service charges 3% + €0.50 per paid ticket. |
| Event Schedule | Attribution Assurance License (permissive) | Yes, the same product | No per-ticket platform fee; the free plan is capped at 25 paid tickets a month, and higher plans are tiered by feature. |
| libreevent | GPLv3 | Self-hosted only | The project is archived and no longer updated, so you maintain the code and server yourself. |
| EventPrime | GPLv2 or later (core plugin) | Runs on your WordPress site | An open-core plugin for WordPress; paid extensions are sold separately and not published. It needs a WordPress site to run. |
| Swicket with alf.io | alf.io is GPLv3 | Engine yes; Swicket is a separate managed service | alf.io is the open source engine; Swicket is a hosted service built on it. |
| Cal.com | MIT community edition (Cal.diy) | Production is proprietary | The production code became proprietary in April 2026; the MIT-licensed Cal.diy is a separate community version. It is a scheduling tool rather than event ticketing. |
| Dandelion | Source-available | Not documented | The code is published to read, but an open licence applies only after a delay, so it is not open source at release. |
A published repository answers only the first column. The other columns decide what you can run and what it costs.
What the licence lets you do
The licences fall into a few groups, and the group matters more than the name:
- Permissive (MIT, Attribution Assurance License), used by Revel and Event Schedule: you can use, change and run the code and keep your changes private, though the licence can still require keeping an attribution notice.
- Network copyleft (AGPL-3.0), used by Chobble Tickets, Hi.Events and Pretix core: you can run and change the code for free, but running a changed version as a service means you must publish those changes under the same licence.
- Copyleft (GPLv3), used by libreevent and alf.io: you can run and change the code for free, and you must publish your changes under the same licence if you distribute the modified program, though not for merely hosting it.
- Open core, used by Pretix and EventPrime: the core is open, and some features are sold as separate proprietary add-ons.
- Source-available, used by Dandelion: the code is published to read, but the open licence applies only after a delay.
- Community edition separate from production, used by Cal.com: the hosted product is proprietary, and a separate MIT-licensed community edition (Cal.diy) carries the open licence.
None of these licences charges a fee to read or run the code. The differences are about republishing changes and which parts are open.
Removing the maker's branding
Whether you can take the maker's name off the software depends on the licence, not only on a paid setting. Revel's MIT licence carries no attribution requirement, so a self-hosted copy can be fully rebranded. Chobble Tickets is copyleft but also sets no attribution requirement, and white labelling is included on every plan.
Other projects keep their name in place unless you pay or upgrade. Hi.Events shows a "Powered by Hi.Events" link on free self-hosting, removed only by a commercial licence. Event Schedule requires attribution under its Attribution Assurance License, and removing its branding needs the Pro plan or above.
The removing platform branding guide compares branding removal across every reviewed provider, open source or not.
What the licence lets a competitor do
Open source licences differ in what a rival business may do with the code. A permissive licence lets any company, large or small, build a closed product on the code and sell it without publishing changes.
Copyleft answers that differently. The AGPL's network clause covers hosted software: a business that runs a changed version as a service must publish those changes, so a competitor cannot take the code, improve it privately and run it as a closed service. Chobble Tickets, Hi.Events and Pretix core use this licence.
Dandelion takes a third path. Its Functional Source License restricts running a competing service for two years, then adds the permissive Apache 2.0 licence, so the original project keeps a head start before the code becomes fully open.
None of this changes an organiser's day-to-day use. It decides who else can build on the software and on what terms, which matters if you plan to fork the code or rely on the project lasting.
Published code is not the same as free hosting
Reading the source does not, by itself, get you a running site. Three separate questions decide what open source is worth to you.
- Can you deploy it? Published source is not always the same code the hosted service runs, and some projects are harder to install than others. The systems a coding agent can deploy guide separates readable code from deployable code.
- What does hosting cost? Most of these providers still charge for their managed service, often per ticket. The flat-rate ticketing and no per-attendee fees guides compare those charges.
- Who runs the server? Self-hosting the open-source core carries no licence fee, though some projects charge to remove branding or for paid add-ons, and it still needs a server and upkeep. The host your own ticket site guide covers what that involves.
A closed alternative sits at the other end. EventMS Pro is self-hosted but ships a licensed build with no source code, so you cannot read or change how it works.
Why source access matters for organisers
Open source lets you check privacy and security claims rather than take them on trust, move to another host that runs the same code, and keep using the software if the original maker stops. Chobble Tickets pairs its published code with encryption of attendees' personal data and a site builder for running separate sites for several organisers.
Related guides group the same providers by other concerns: ethical ticket sales options, UK-made ticket platforms and removing platform branding.