There is a file size limit of 6mb for free users.
The converter will create an Ableton Live 9.7/10.1 or FL Studio 12.5 project file. They should open fine in newer versions of the DAW.
The "Relative Path" option will look for samples in the same folder as the newly generated file, instead of using the existing filepaths. Only for ALS->FLP already does this by default.

There is currently no support for instrument/effect racks or Patcher. If you have a native synth (like Operator or 3xOsc) in your project, it will default to a Operator/3xOsc synth.
Ironically, you currently can't convert from a jukeblocks template/converted file, because they are minimized versions of a full project file. If you save the project at least once in the DAW, it will convert fine afterwards.

If warping is creating clicks, I recommend making sure warpmarkers are placed on the quiet part of a waveform (before a transient), as the warpmarker is where a cut will be made in FL, which is where a click can happen.
This converter was made with Ableton 10 and 11 in mind and doesn't work when converting from Live 8 or lower.

FLPs don't store the bpm of samples in the file, so if you have time-stretched samples you can write "120bpm" or whatever tempo it is in the channel name.
Sample paths may not convert properly on versions of FL Studio before 20.7.2
Both of these issues can be resolved by converting using a zip file (see Zip Files section).

Only FL Studio 12 and up is supported.
To make use of Send/Return Tracks, maybe sure they are docked to the right in FL.
Some of the stock/default FL samples don't work in Ableton.
Some features are not available if you make an Ableton 9.7 file, such as converting VST3 plugins or any automation.

You can downgrade Ableton Live 12, 11 and 10 files to an earlier version of Ableton like 10.1 or even 9.7.
Plugins and features that are exclusive to Ableton 12/11 won't be available in 10 or 9 of course. In most cases they will be removed in the downgraded file.
Ableton 9 has more limitations, such as no VST3 plugin support, automation or groups in groups, so only the top level groups will be kept, and all the audio/midi tracks inside will become part of that group.

If you are downgrading to a lower edition version (Like Suite to Standard) you will need to remove the native plugins/max for live devices not allowed in your edition before you can save/export.
A full list can be viewed here: https://www.ableton.com/en/live/compare-editions/
Then you will need to reauthorize Ableton from the settings. If all interfering plugins have been removed, it should allow you to save again like normal.
A better solution will come out eventually.

You can upload a zipped project file including its samples.
This has multiple benefits, from easier sample management when sending the project to other people, to more accurate audio time-stretching when converting from FLP -> ALS.

In FL Studio go to File->Export->Zipped Loop Package to collect the flp and all used samples into a zip file that can be used for converting.

In Ableton go to File->"Collect All and Save" to collect all the used samples to the project folder (I usually only tick the first three boxes), then zip the project folder yourself and convert.
Note: If you have multiple als files in the same project folder it will only convert the first.
-> ->
Jukeblocks will decompress the zip, scan the audio files and then recompress the converted project file back into the zip file.
You can actually open the converted zip files in FL Studio without unzipping it first (although if you plan on saving I don't recommend this).
Note: M4A Files aren't supported in FL Studio so won't be carried over during conversion.
Future updates will allow for audio file manipulation, so that your files can reverse when converting from FLP -> ALS (Ableton doesn't actually play audio backwards but creates a new file instead).

You can now convert some plugins from AU (Audio Unit) to VST2.
This feature is still in development as in many cases each AU/VST pair need their own custom solution.
Therefore not all Audio Units are supported at the moment.
The current list includes Xfer Serum, Vital and plugins from Native Instruments (Massive, Kontakt), iZotope and Kilohearts.
If you would like to see an Audio Unit plugin supported, please send a project file including the AU and VST2 version of the plugin, preferably with a matching preset, to contact@jukeblocks.io
There may be support for VST3 in the future. Especially for plugins that only have a VST3 version available.
When converting AU to VST2, to an FLP file, some plugins may not open even when supported. This is because FL Studio doesn't know the plugin's unique ID. If you "Verify Plugins" using the plugin manager, this should resolve that issue.

You can downgrade any Serum synth presets in preset file (.fxp) or within a supported project file (currently only ALS and FLP).
The format will downgrade to version 1.07b3, one of the earliest publicly available formats.
Newer features that were added to Serum after this version, such as the additional 4 LFOs, extra few filters and distortion types will be removed.
If you want to downgrade Serum presets without converting or downgrading an entire project file, select the "Keep Same Version" from the DAW list, when selecting "Downgrade Serum".
Support for SerumFX is not available at this time.

If you have any FL Studio score files, they can now be converted to MIDI. You don't need to select a format to convert to in the menu as MIDI is the only thing it will convert too.
Please be aware that any FL Studio note specific features like Slide notes or Portamento notes will just convert to regular notes in MIDI.

Sept 2: ALS->FLP: Improved the audio clip conversion greatly. Samples with multiple warp markers will now convert accurately to FL Studio.
As FL Studio currently has no native warp marker support, each warp "zone" now turns it's own clip on the playlist.
Previously, this would only work accurately for the first one or two markers, meaning a lot of heavily warped samples were converted poorly.
Glad this has finally been added!

July 13: You can now convert AU plugins to VST2 plugins! This is still a work in progress and not all plugins are supported yet. Please read the AU -> VST2 tab for more info.

June 16: You can now downgrade Serum presets within project files!
If you want to downgrade Serum inside a project file without converting it, select the Keep Same Version item from the menu, and tick the Downgrade Serum box.
When the tick-box is selected, you will also downgrade any Serum presets during a conversion between DAW formats.

May 25: You can now downgrade Serum presets. Currently supports .fxp presets. Presets within project files will be added soon.

April 3: Live 12 downgrade support has been added. It can now downgrade to Live 10 and 9. You will be able to open a Live 10 file in Live 11 of course.
MaxForLive devices had to be removed because Max Devices saved in newer Ableton versions get updated and can't be opened in an older version.
If you have the original Max Device file, you may be able to drag it in again if it's old enough.

March 19: FLP->ALS: Added support for Hold automation mode and made channel rack sequencer notes not be extremely small.

Sept 23: Added Downgrade for Ableton as well per request. It's not perfect (notably automation and mixer settings don't work at the moment), but will at least open.
If you already "Collected All and Saved" then you'll need to put the downgraded file in the same directory as the Ableton 10 file.

May 4: FLP->ALS: Midi notes in Audio Clips will turn into a unique midi track. Previously these were skipped because it was considered an audio track by the converter.
Using Samplers over Audio Clips is still better in my opinion, but this should allow for more flexibility.

Dec 17: FSC (FL Studio Score file) to MIDI is now supported!

Dec 17: FL 21 files should work but I've only done limited testing so let me know if something breaks! I'm planning on adding fades between ALS and FLP soon.

Sep 22: Added support for Fruity (Free) Filter and Auto Filter. Only the frequency can be automated for now.

Sep 20: Ableton's Midi Pitcher now links to an FL Studio channel's root note and vice versa. If you have multiple Midi Pitchers they will stack up.

June 22: AIFF files are now supported when converting zip files. No support for M4A files as they currently can't be used in FL Studio.

June 5: FLP->ALS: Midi in a Layer channel will move to it's set children.

June 1: Improved automation handling from FLP to ALS. Weird curves like Smooth Stairs will still default to Single Curve 1, but otherwise it's much more usable now.

May 23: Another one. Native FL Studio plugins Harmor, Sytrus, Slicex, Love Philter, Delay 2, Vocodex (no routing), Grossbeat and Waveshaper will now open as a vst format in Ableton.
You can find the vst versions on Image-Line's vintage subdomain or on third party vendors if you google.
I don't know if it's necessary to convert the vst back to their native version just yet (as IL vst plugins still work in FL), but that will probably come in a future update.

May 22: Another update! The converter now supports conversions between Drum Rack and FPC.
FPC only has 32 drum pads while Ableton's Drum Rack has 128 so it will only work with the first 32 pads for now.

May 17: The converter will now convert Fruity Balance/Utility and EQ8/Parametric EQ 2. Go nuts, go crazy!
Some quirks: The Q of EQ8/Parametric EQ 2 is close but not perfect, and isn't automatable for now.
ALS->FLP: In Utility, only the Gain and Balance (Panning) convert for now (because those are the only parameters in Fruity Balance). A future update will use patcher to add the remaining parameters.
ALS->FLP: EQ8 has 8 bands, Parametric EQ 2 has 7.... skipping the 8th band for now.
ALS->FLP: When being automated, Balance will be limited by a max gain of +5.6dB, unlike Utility's +35dB. When not automated it isn't limited.

March 24: There is now support for groups and chained insert tracks (when using the New Features option)!
Finally if you have busses or multiple mixer tracks in FL, you'll be able to convert them over to Ableton too.
The converter will only use one output routing for inserts (and any that go to a send).
Groups will work from ALS -> FLP as well, including if you use the Sends Only routing option.
As there's no groups in groups for Live 9 you'll have to deselect the New Features for now if you specifically need a Live 9 file.

March 16: Support for Sends/Return Tracks has been added. This is accessible via the "New Features" button for now, which is like a beta testing mode.
Often I'll make changes which may have unforeseen consequence. This way I can add new features while still allowing safer conversions in case anything crashes.
Please still send any project files if they crash so I can fix them!

Nov 28: Work is still actively being done on the converter. I tend not to update every minor update or bug fix here but I still work on improving it and making sure newer versions of project files are also supported.

Sept 2: You can now upload zip files of project files. This can be helpful for collaborating or better conversions. Read the new "Using Zip Files" section for more information.
It also seems like a long time since the last update but I don't report all the bugfixes that have helped make the conversions much smoother over the months.

March 24: Some vst2 plugins would reset like OTT and FabFilter plugins when converting. This has now been fixed!

March 20: Big update! Automation has now been added to the converter! Currently all third party plugin automation should work fine, plus automation for the volume fader. More parameters will follow soon, plus curves.
As this is a new feature I've just added support for, it's currently in "beta/early access" so you can decide not to use automation in case it breaks the conversion process. Plus still send the broken project file to me and I'll try to fix it.
Automation isn't supported converting to (or from) Live 9, just 10 and up for now.

Feb 27: Hello Mac users. AU plugins will now be able to convert between project files too. This should mean all plugins (besides native ones) should be able to be converted now! No more plugin limitation :)

Feb 25: Ableton Live 11 has been released! So far the conversions seem to work fine between Live 11 and FL Studio.
I've also added a new option to downgrade from Ableton 11 to Ableton 10 or even 9. This also adds a new menu so you can choose which version to downgrade to.
Converting between FLP and ALS works the same too, but you can now choose which Ableton version you want to generate (as Live 9 doesn't have VST3 support).

Feb 21: Awww yeahh. VST3 plugins are now supported! This is new so let me know if you find any issues with converting them.
Because VST3 plugins were not supported before 10.1, if you want to convert a project file for Live 9, you must have the "Convert VST3 plugins" unticked, (on by default). This only matters when converting to Ableton/ALS.

Feb 18: Added some gradients to the tracks and clips now. No more only yellow.

Feb 3: Proud to announce the fader conversion is perfect now! Happy converting :)

Feb 2: Improved volume fader conversion greatly. Not 100% perfect on low volumes, but near perfect for everything else.
Made a custom message for Ableton 8 (or earlier) project files, as they aren't supported and would error.