T4
a versioned datastore with branching and time-travel (S3-backed)
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Hi HN,I built t4, a datastore that stores its WAL and snapshots in S3.Instead of traditional storage, it writes append-only segments to object storage and reconstructs state from checkpoints + WAL.A side effect of this model is that the database becomes naturally versioned: you can restore any past state, branch from any point (with copy-on-write) and replay historyI started this as an experiment to replace etcd in Kubernetes, but it’s evolving into a general-purpose versioned state store.Curious what people think about it and appreciate any feedback!
HN · launched Apr 12, 2026 · 7 upvotes (top 61%) · 0 views
Niche: database management systems and engines · 162 launches, 5 in the last 7 days ▼ -17% · Explore this niche →
Category and tags
- Horizontal
- Data infrastructure
- Developer
- Not AI
- Commercial product
Visit website ↗ Source listing ↗
More like this: all 162 launches in database management systems and engines →
Could you build this?
No Designing a reliable ACID-compliant, branching, time-travel datastore backed by S3 with write-ahead logs, checkpointing, and cache invalidation requires advanced distributed systems and database engine expertise.
What it would actually take: Building this requires a custom storage engine written in Rust or Go implementing an LSM-tree or append-only segment log architecture integrated with an S3 object store. The difficult technical challenges involve distributed consensus, high-concurrency WAL flushing, handling S3 eventual consistency/latencies, zero-copy snapshot compaction, and transactional isolation during branching. It demands specialized distributed systems engineering that AI prompting cannot architect or verify for correctness.
Discussion
2 comments analyzed.
Feature requests: Node.js client support, Python client support
Competitors
Other products that read as similar to this one : 105 launches clear the similarity bar, closest 8 shown.
Attention rank: #67 of 106 (itself plus its competitors, highest first, normalized so YC and Product Hunt are compared fairly).
Launched 162 days after the earliest competitor.
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- Raptyra · ph · 2026-10-04 · 1 upvotes · similarity 0.43
- SirixDB 1.0 Beta · hn · 2026-07-15 · 13 upvotes · similarity 0.42
- Portabase · hn · 2026-01-08 · 6 upvotes · similarity 0.41
- UnisonDB · hn · 2025-11-01 · 17 upvotes · similarity 0.41
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