head to head · open source
cobalt vs sill
cobalt has 44,992 GitHub stars, 3,972 forks, 269 open issues and last shipped 6 months ago. sill has 979 stars, 51 forks, 53 open issues and last shipped yesterday. cobalt leads on adoption by 4,496% (44,992 vs 979 stars). cobalt is written in Svelte under AGPL-3.0; sill is written in Swift under Apache-2.0. cobalt has attracted 9% as many forks as stars, sill 5%. sill was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| cobalt | sill | |
|---|---|---|
| GitHub stars | ★ 45K | ★ 979 |
| License | AGPL-3.0 | Apache-2.0 |
| Written in | Svelte | Swift |
| Last push | 2026-04-06 | 2026-10-14 |
| Forks | ⑂ 4.0K | ⑂ 51 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick cobalt if
- You weight community size — 45K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Svelte
- You value the larger contributor base for long-term maintenance
pick sill if
- You want the sill feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Swift
- You evaluated both and sill fits your workflow better
About cobalt
cobalt is a media downloader built around a single promise: paste a link, get the file, move on. It is a monorepo containing the source for an API, a web frontend, and related packages, written primarily in Svelte and TypeScript. The project lives in the modern web and JavaScript ecosystem, and its public surface is hosted at cobalt.tools, while the full codebase is published under the AGPL 3.0 license.
read the full cobalt overview →
About sill
Sill is a free, open source app that streams any window, or the whole desktop, from an Apple silicon Mac to an iPhone or iPad, where it is driven by touch, trackpad, keyboard or Apple Pencil, with no account and no server in between.
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Frequently asked questions
Is cobalt or sill more popular?
cobalt has 44,992 GitHub stars and sill has 979. cobalt has the larger community by that measure.
Are cobalt and sill free?
Both are open source. cobalt is licensed under AGPL-3.0 and sill under Apache-2.0. Neither carries a licence fee.
What is the difference between cobalt and sill?
cobalt is written in Svelte and sill in Swift. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, cobalt or sill?
Choose cobalt if you want the larger community (44,992 stars) or its AGPL-3.0 licence terms. Choose sill if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.