TechnicSolder is an API that sits between a modpack repository and the TechnicLauncher. It allows you to easily manage multiple modpacks in one single location.
Using Solder also means your packs will download each mod individually. This means the launcher can check MD5's against each version of a mod and if it hasn't changed, use the cached version of the mod instead. What does this mean? Small incremental updates to your modpack doesn't mean redownloading the whole thing every time!
Solder also interfaces with the Technic Platform using an API key you can generate through your account. When Solder has this key it can directly interact with your Platform account. When creating new modpacks you will be able to import any packs you have registered in your Solder install. It will also create detailed mod lists on your Platform page!
TechnicSolder was originaly developed by Technic using the Laravel Framework. However, the application is difficult to install and use. Technic Solder - Solder.cf by TheGameSpider runs on pure PHP with zip and MySQL extensions and it's very easy to use. To install, you just need to install zip extension, setup MySQL database and extract Solder to your root folder. And the usage is even easier! Just Drag n' Drop your mods.
On January 1st, 2019 I released Solder.cf version 1.0.0. I created something better than I expected. The best thing about this application - it automatically process your .jar files. You can upload hundreds of mods at once, and the application can extract mod information like author or version from these files, zips them and saves them to your data storage and MySQL database. With simple GUI you can create and publish modpacks in seconds.