pquerna/ffjson

Health v2 · maintenance only

Flags: no_releases

Adoption not part of the score

2993 stars · 234 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

ffjson is a Go code generator that emits static MarshalJSON and UnmarshalJSON functions for your struct types, removing the runtime reflection overhead of encoding/json. The generated code is a drop-in replacement implementing the standard encoding/json interfaces, typically making serialization and deserialization 2 to 3 times faster with no changes to calling code.

Use cases

• speed up JSON serialization in Go
• avoid reflection overhead when encoding Go structs to JSON
• generate MarshalJSON and UnmarshalJSON implementations for my structs
• find a faster drop-in replacement for encoding/json
• optimize high-throughput JSON parsing in a Go API
• reduce JSON encoding CPU cost in hot code paths

When to choose

• JSON marshaling/unmarshaling shows up prominently in your Go application's CPU profile
• you want to keep full compatibility with the encoding/json interfaces and fall back to it automatically for unsupported types
• your struct definitions change rarely, or you can wire code generation into your build process

When to avoid

• your structs change frequently and regenerating code on every change is impractical
• your JSON workloads are small enough that encoding/json performance is not a bottleneck
• you prefer runtime drop-in serializers that require no code generation step

Facets

cli-tool · maturity maintenance

serialization json cli developer-tools developer-tools web-development apis performance go cli cross-platform code-generation go-codegen drop-in-replacement reflection-free marshaljson unmarshaljson json-serialization encoding-json

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