T4
a versioned datastore with branching and time-travel (S3-backed)
Details
- External ID
- 47742167
- Source
- HN
- Company
- —
- Product
- T4
- Website domain
- github.com
- Launched
- April 12, 2026
- Cohort
- —
- Upvotes
- 7
- Upvotes percentile
- 0.38817480719794345
- Tags
- —
- Fetched at
- Sept. 7, 2026, 9:26 p.m.
- Updated at
- Sept. 7, 2026, 9:26 p.m.
Description
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!
Enrichment
- Theme
- Vertical
- Horizontal
- Function
- Data infrastructure
- Audience
- Developer
- AI stance
- Not AI
- Project type
- Commercial product
- Normalized one-liner
- versioned datastore with branching
- Manually corrected
- False
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 — 57 launches clear the similarity bar, closest 8 shown.
Attention rank: #39 of 58 (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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- SirixDB 1.0 Beta · hn · 2026-07-15 · 13 upvotes · similarity 0.41
- Quorum-free replicated state machine built atop S3 · hn · 2026-01-31 · 6 upvotes · similarity 0.41
- Portabase · hn · 2026-01-08 · 6 upvotes · similarity 0.40
- UnisonDB · hn · 2025-11-01 · 17 upvotes · similarity 0.40
- DeltaGlider · hn · 2025-11-12 · 8 upvotes · similarity 0.40
- Renovate · hn · 2026-02-11 · 43 upvotes · similarity 0.39
Other launches for this product
- No other launches for this product.
Same idea, different domain
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