About Trefle
Trefle is an open botanical data source and REST API, maintained by a small volunteer team and backed by Mashum. It indexes about one million plants and is free for everyone.
Data sources
Records are gathered from institutional databases, reconciled on the accepted scientific name, and completed by hand by contributors. Each species page states which sources it draws from and links back to them.
Data is gathered from
and completed by hand by contributors around the world.
The team
Trefle started in 2016 and is run by volunteers: developers, data reviewers and contributors who correct species pages. Hosting and research are covered by donations and by Mashum association.
- 1
- core maintainers
- 0
- data reviewers
- 8
- contributors this year
Want to help? See how to join the team.
Pricing and limits
Trefle is free for all, and always will be. Server maintenance is expensive, so requests are rate-limited.
Licence and citation
The API and platform code are open source under AGPL-3.0. The Trefle database — the compilation, its structure and the community corrections — is published under CC-BY-4.0. Individual records aggregate facts from the upstream sources listed above, and each upstream source keeps its own licence. Images carry their own attribution.
Using Trefle in an app? Display “Data: Trefle.io (CC-BY-4.0)” with a link back to trefle.io. Publishing research? Read the full citation formats and DOI and the terms of use.
To cite Trefle in a publication:
Trefle (2026). Trefle: a global plants API. https://trefle.io — data licensed CC-BY-4.0, accessed 2026-09-16.
(very short) privacy policy
Trefle.io take your privacy seriously and will take all measures to protect your personal information. We store your e-mail, your API token and your corrections. We will not sell or redistribute your information to anyone. No third-party tracking.
Contact
Questions, partnerships, datasets to integrate, educational projects — write to us. We reply to every message, usually within a few days.