# RuedigerMoeller/fast-serialization

FST: fast java serialization drop in-replacement

Repository: https://github.com/RuedigerMoeller/fast-serialization
Canonical: https://ross.abutalabs.com/products/fast-serialization
Language: Java
License: Apache-2.0
License Family: permissive
Topics: serialization, json, java, offheap, faster
Last push: 2023-06-30T08:15:18+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 4654, "days_push": 1160, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1595, forks 236 (observed 2026-08-28T04:05:09.120999+00:00)

## What it is
FST is a fast, JDK-serialization-compatible drop-in replacement for Java object serialization, also offering JSON encoding of serializable object graphs and off-heap/persistent maps. It includes FSTStructs for packed-object-style memory layouts and the MinBin cross-platform binary format.

## Use cases
- speed up java serialization of object graphs
- replace jdk serialization with a faster drop-in
- serialize objects to  including shared references
- store large maps off the jvm heap
- persist off-heap maps to disk
- serialize lambdas and complex graphs on android

## When to choose
- you need faster binary serialization compatible with java.io.Serializable
- you want off-heap data structures to reduce GC pressure
- you need JSON output of full object graphs with reference handling

## When to avoid
- you need a modern actively developed serialization library
- you cannot use incubator foreign memory APIs on java 14+ for the 3.x line
- you need cross-language schema evolution like protobuf or avro

## Facets
- artifact type: library
- maturity: maintenance
- function: serialization, caching
- domain: developer-tools, performance, databases
- platform: jvm
- tags: java-serialization, offheap, drop-in-replacement, binary-format, minbin, android

## Member repositories
- RuedigerMoeller/fast-serialization (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:09.120999+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:54:05.659421+00:00, confidence not recorded.
  - readme: https://github.com/RuedigerMoeller/fast-serialization (fetched 2026-08-28T04:05:09.120999+00:00, sha 382f3251cfe2)
- Data as of 2026-08-30T08:39:29.467469+00:00.