I followed Connect a local parachain tutorial and successfully run my local parachain node with this command:

./target/release/parachain-collator \
--alice \
--collator \
--force-authoring \
--chain rococo-local-parachain-2000-raw.json \
--base-path /tmp/parachain/alice \
--port 40333 \
--ws-port 8844 \
-- \
--execution wasm \
--chain <relay chain raw chain spec> \
--port 30343 \
--ws-port 9977

But while follow Connect to Rococo testnet tutorial, I don't know how to fill the <relay chain raw chain spec> field to start local parachain node. Do I need the chain specification file of Rococco testnet to run my local parachain node?

1 Answer 1


In order to connect your parachain to a relay chain you need its chain spec file.

In the tutorial, the relay chain you want to connect is rococo. The chain spec is public: https://github.com/paritytech/polkadot/blob/master/node/service/chain-specs/rococo.json

I suggest to download this file in your node and run the same command with:

--chain ./rococo.json \

You can see the spec files of other public networks: https://github.com/paritytech/polkadot/tree/master/node/service/chain-specs

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.