MongoDB to S3
real-time replication
TwinCommit replicates MongoDB to Amazon S3 in real time by reading the MongoDB transaction log and applying every committed change exactly once and in commit order. Use it to land live MongoDB data in S3 as open Delta Lake or Iceberg tables, with no triggers or capture tables on the source.
MongoDB
log reader
commit-ordered · exactly-once
S3
native writer
How capture works on MongoDB
TwinCommit opens change streams on replica sets and sharded clusters, persists resume tokens with the checkpoint, and keeps multi-document transactions intact.
Prerequisites
- ✓Replica set or sharded cluster (change streams need an oplog)
- ✓changeStream and find privileges on watched databases
- ✓Pre- and post-images enabled for full before/after values (optional)
How apply works on S3
Changes land as Apache Iceberg, Delta Lake or Parquet tables, one atomic commit per micro-batch with the checkpoint in the snapshot metadata. Iceberg tables register in AWS Glue or Amazon S3 Tables automatically.
Requirements
- ✓IAM role with s3:GetObject, PutObject, DeleteObject and ListBucket on the prefix
- ✓Glue catalog permissions for table registration
- ✓Same-region placement recommended
Setup
Set up MongoDB → S3 in four steps
- 1
Prepare MongoDB
Run twincommit check. It verifies replica set or sharded cluster (change streams need an oplog) and the other prerequisites, and prints the exact fix for anything missing.
- 2
Point at S3
Add a target block for S3. TwinCommit can generate target DDL with twincommit ddl -apply.
- 3
Snapshot
twincommit snapshot copies each table under a brief share lock and records the exact log position.
- 4
Stream
twincommit run streams every committed change from that position, exactly once and in commit order.
source:
type: mongodb
uri: ${MONGODB_URI}
target:
type: s3
bucket: acme-lake
path: replica/{schema}/{table}
format: iceberg
catalog: { type: glue, database: replica }
tables:
- source: sales.orders
- source: sales.customersMongoDB to S3 replication FAQ
How does TwinCommit replicate MongoDB to S3?
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TwinCommit reads changes from the MongoDB transaction log, buffers them per transaction, and applies each committed transaction to S3 in commit order. Changes land as Apache Iceberg, Delta Lake or Parquet tables, one atomic commit per micro-batch with the checkpoint in the snapshot metadata. Iceberg tables register in AWS Glue or Amazon S3 Tables automatically.
Does MongoDB to S3 replication need triggers or capture tables?
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No. TwinCommit reads the MongoDB log directly and creates no objects in the source database.
Is MongoDB to S3 replication exactly-once?
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Yes. TwinCommit commits its checkpoint in the same S3 transaction as the data, so a crash or restart never loses or duplicates a transaction.
What MongoDB versions are supported?
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MongoDB 5.0–8.x · MongoDB Atlas · replica sets and sharded clusters.
Stream MongoDB to S3 today.
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