Today the decdn public testnet is live on Arbitrum Sepolia, and the code is open source. You can download something real from the network right now with one command, and if you have data of your own to distribute, you can run it through the testnet with us.

The problem we kept hitting

Big files are awkward to move. Model weights, datasets and install images run to tens of gigabytes, and they reach you from an origin, a CDN edge or a mirror. Whichever one you land on, the download usually comes from that single server. When it throttles you, rate-limits you, or has a bad afternoon, you wait.

What decdn does

Independent nodes cache content and serve it, and every file is addressed by its BLAKE3 hash. The client checks each piece against that hash the moment it arrives. A piece that fails is thrown out and fetched again from another node, so you end up with exactly the bytes the publisher named, without trusting any machine in between. Large files are pulled from several nodes at once.

Delivery is paid per megabyte, in USDC, as the bytes arrive. The target rate is $0.01/GB, 4 to 20 times cheaper than major traditional CDNs. It is a target, not a protocol-enforced price: nodes set their own rates, and every client can cap what it is willing to pay.

Try it

The homepage has a catalogue of things we seeded on the testnet: open model weights (Mistral 7B Instruct, Qwen2.5 7B Instruct, Whisper large-v3 and Stable Diffusion XL), the LibriSpeech speech corpus, Ubuntu and Debian install images, and two Blender open movies in 4K. Pick one and it shows you the exact line to paste.

For Mistral 7B Instruct, on macOS or Linux, in a terminal:

curl -fsSL https://up.decdn.org/decdn.sh | sh -s -- get 'decdn:9194000d7b356650e6924a7746ec4afb0b705838b65913c0e46cba6b15af69e5/?ns=1'

On Windows, in PowerShell:

& ([scriptblock]::Create((irm https://up.decdn.org/decdn.ps1))) get 'decdn:9194000d7b356650e6924a7746ec4afb0b705838b65913c0e46cba6b15af69e5/?ns=1'

The line installs decdn, opens one captcha in your browser, then downloads into the current directory and verifies every byte on the way in. If it gets interrupted, run the same line again and it resumes. On the testnet a sponsor covers the transfer with a capped allowance, so there is nothing to pay and no account to make.

While it runs, you can watch the network work at stats.decdn.org: settlements and the node fleet, read straight off Arbitrum Sepolia. The whole thing is open source at github.com/decdn/decdn: the node, the client, the contracts, and more than two dozen design records covering the payments, the slashing and the verification.

Bring your own data

The catalogue is what we seeded. The more useful test is your data, so we're opening pilots on the testnet. If you distribute content of any kind or size, we set up an origin node in front of your storage with you, publish a real catalogue from it, and wire the client into whatever does your downloading. You measure the result on your own files, and delivery during the pilot draws from a pool we fund, so there is nothing for you or your users to pay. Write to [email protected] to start one. Who actually needs this covers the workloads where it helps most.

What testnet means

The money is testnet money, and things will break. When they do, tell us: open an issue on GitHub, find us on Discord, or write to [email protected].