Fluid Topics supports the following interface languages:
| Language | Code |
|---|---|
| Bulgarian | bg-BG |
| Chinese (China) | zh-CN |
| Chinese (Taiwan) | zh-TW |
| Czech | cs-CZ |
| Danish | da-DK |
| Dutch | nl-NL |
| English (UK) | en-UK |
| English (US) | en-US |
| Estonian | et-EE |
| Finnish | fi-FI |
| French (Canada) | ft-CA |
| French (France) | fr-FR |
| German | de-DE |
| Greek | el-GR |
| Hungarian | hu-HU |
| Icelandic | is-IS |
| Indonesian | id-ID |
| Italian | it-IT |
| Japanese | ja-JP |
| Korean | ko-KR |
| Latvian | lv-LV |
| Lithuanian | lt-LT |
| Norwegian | no-NO |
| Norwegian (Bokmål) | nb-NO |
| Polish | pl-PL |
| Portuguese (Brazil) | pt-BR |
| Portuguese (Portugal) | pt-PT |
| Romanian | ro-RO |
| Russian | ru-RU |
| Spanish (Latin American) | es-419 |
| Spanish (Mexico) | es-MX |
| Spanish (Spain) | es-ES |
| Swedish | sv-SE |
| Turkish | tr-TR |
| Ukrainian | uk-UA |
| Vietnamese | vi-VN |
The Administration menu is only available in four languages: English, French, German and Japanese.