Test Locally

You can run a Substreams server locally to run e2e testing.

It requires a local copy of full merged-blocks files for the range you want to test over. You can easily download those files from a Firehose endpoint.

Then run the Substreams software locally, and run tests against it

Install binaries

Install the firehose-core single binary for most chains (those without chain-specific extensions) with brew:

brew install streamingfast/tap/firehose-core

or get a release from: https://github.com/streamingfast/firehose-core/releases

Download merged blocks locally

Run against an endpoint for the chain you're interested in. For example:

fireeth tools download-from-firehose mainnet.eth.streamingfast.io:443 1000 2000 \

which will download merged blocks to your local disk. You might need to be authenticated.

Run the Substreams engine locally


fireeth start substreams-tier1,substreams-tier2 --config-file= \
  --common-live-blocks-addr= --common-first-streamable-block=1000 \


  1. the --common-first-streamable-block must be the lowest block available on disk, otherwise the server will fail to start.

  2. if you need to do eth_calls with the Ethereum, you can add: --substreams-rpc-endpoints https://example.com/json-rpc/somekeysometimes

  3. the --substreams-state-bundle-size=10 flag will write smaller stores snapshot, suitable for dev

This will run a fully workable stack

Stream against your local instance

Test with:

substreams run -e localhost:10016 --plaintext \
  https://spkg.io/streamingfast/ethereum-explorer-v0.1.2.spkg \
  map_block_meta -s 1000 -t +10

and enjoy.

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