Serialize R Objects to JSON • RJSONIO

RJSONIO converts R objects to and from JSON. It provides a stable API for serializing R vectors, lists, data frames, arrays, environments, and S4 objects, and for reading JSON from strings, files, and connections.

The package is maintained as a compatibility-first JSON implementation for R. Its main value is stable behavior for established R workflows, plus extension points such as parser handlers, callbacks, S4 methods, connection parsing, and custom serialization methods.

Installation

Install the CRAN release:

install.packages("RJSONIO")

Install the development version from GitHub:

install.packages("remotes")
remotes::install_github("YaoxiangLi/RJSONIO")

Quick Start

library(RJSONIO)

x <- list(
  id = 1,
  name = "RJSONIO",
  values = c(1, 2, 3),
  active = TRUE
)

json <- toJSON(x, pretty = TRUE)
cat(json)

fromJSON(json)

Validate JSON before parsing:

candidate <- toJSON(list(name = "RJSONIO", version = "2.0.5"))
isValidJSON(I(candidate))

Round-trip common R objects:

value <- list(a = 1, b = c(TRUE, FALSE), c = c("x", "y"))
identical(fromJSON(toJSON(value)), value)

When RJSONIO Fits

RJSONIO is a good fit when a project already depends on its parsing or serialization behavior, or when code needs callback-based parsing, S4/object serialization, or explicit control over JSON generation.

For new projects that mainly consume web APIs or tidy tabular JSON, compare the available R JSON packages and choose the one whose mapping and performance match the job. The package website includes a comparison-oriented benchmark article and examples of RJSONIO’s customization points.

Compatibility

The unit test suite includes compatibility coverage for parsing, serialization, simplification modes, encodings, connections, edge cases, and string callbacks. Changes to existing behavior should be deliberate, tested, and described in NEWS.md.

Documentation

Package website and articles: https://yaoxiangli.github.io/RJSONIO/
CRAN page: https://CRAN.R-project.org/package=RJSONIO
Issues: https://github.com/YaoxiangLi/RJSONIO/issues

Development

Run the unit tests:

testthat::test_local()

Run a package check:

R CMD build RJSONIO
R CMD check --no-manual RJSONIO_2.0.5.tar.gz

Optional benchmark scripts are kept under benchmarks/. They are intended for local comparison work and are excluded from CRAN package builds.