Limits

Know the boundaries

Area	Current boundary
Workspace throughput	Each workspace has one writer: its Durable Object.
Retry deduplication	Receipts have no expiry. The operation hash is removed after half the history retention, 15 days by default; afterwards, reusing the id acknowledges the original write regardless of its body. Legacy upgrades and restores preserve a fixed boundary for missing receipts.
Reads	No fixed row cap; wide reads stream in keyset chunks of 1,000 rows.
Bulk writes	Any number of rows in one transaction; applied optimistically and queued offline like any write.
Relations	Relation filters and nested creates nest without limit, typed at every depth, and filters can be any length.
Live windows	No fixed row cap; every loaded page stays live and streams in keyset chunks of 1,000 rows.
File access	Per file: role(), fileCheck() or attachedTo() a row, decided by the workspace before bytes move. See File access.
File uploads	Any size: past 16 MiB, files go up as R2 multipart uploads (objects up to 5 TB). File bytes live in a separate R2 bucket.
Presence and broadcast	Ephemeral, over the workspace socket; socket messages of any size (large ones travel in parts), and a socket holds any number of live queries. Broadcast messages are not stored or replayed.
History retention	Deleted and overwritten values leave every TapeDB copy within the retention (30 days by default). Cloudflare keeps 30 days of Durable Object point-in-time recovery regardless; see Privacy & data.
Claim route	Rate-limited by default: 300 requests per IP and 30 per subject, refilling over 60 seconds; exact and global. Configurable with identity.limits.

The API is frozen; see API stability for what may still change.