Explore the code Idempotent writes
A retry does not double a row.
Chain data in SQL
Chain data in your database.
Without the pipeline.
Postgres or ClickHouse, with the writes, the checkpoints and the reorganizations already handled.
- Postgres and ClickHouse
- Idempotent writes
- Reorg aware
- Hosted or self-run
Ethereum → Firehose → Substreams → PostgreSQL
Interactive illustration
StreamingFast
ecosystem
01 Chain data in SQL
Looks familiar?
A retry ran twice and a balance doubled, and you found out from a customer.
The chain reorganized and your table still holds the number that was true for ninety seconds.
The stream reconnected, and nobody can prove it resumed at the right block.
Want to see your own schema filled?
See Hosted Sinks
RUST → WEBASSEMBLYThe hard part is not the connection.
Getting data into a database is an afternoon. Keeping it correct through retries, reconnections and reorganizations is the job, and it has no end date. A hosted sink is that job, run for you: writes are idempotent by construction, progress is versioned by block, and a reorganization reverses what it has to and leaves the rest.
Read the guideFilterMapAggregateDeliver
▧ substreams.yamlPACKAGE STRUCTURE
01 specVersion: v0.1.0
02 package:
03 name: token_transfers
04 version: v0.1.0
05
06 modules:
07 - name: map_transfers
08 kind: map
09 inputs:
10 - source: sf.ethereum.type.v2.Block
11 output:
12 type: proto:transfers.Transfers Illustrative excerpt Build a complete package ↗
What you get
Block-versioned progress
A reorganization unwinds exactly what it should.
Postgres and ClickHouse
Two supported destinations, same contract.
Hosted or self-run
Let it run for you, or run it yourself. The behaviour does not change.
A schema you declare
You define the tables. Nothing is invented on your behalf.
02 Chain data in SQL
How it works
FROM HISTORY TO THE CHAIN HEAD
Historical blocksNew blocks
TRANSACTIONS
TRACES & LOGS
STATE CHANGES
Rich block data. One continuous stream.
Declare the schema
The tables, and the keys that make a write idempotent.
Deploy the sink
A form and a deploy button, or your own process.
Let it unwind
Reorganizations arrive as signals, not as numbers that silently change.
Want to see your own schema filled?
See Hosted Sinks03 Chain data in SQL
What you stop owning
[01]
The glue between the stream and the database
[02]
The checkpoint logic, and the day it is wrong
[03]
A standing percentage of an engineer, forever, for repair
Chain data in SQL
Put it in your database, not in a demo.
Read the guide ↗Build a reliable blockchain-to-SQL pipeline
Choose the mapping, preserve progress and operate ingestion with clear freshness and cost expectations.