The serializeJSON and unserializeJSON functions convert between R objects to JSON data. Instead of using a class based mapping like toJSON and fromJSON, the serialize functions base the encoding schema on the storage type, and capture all data and attributes from any object. Thereby the object can be restored almost perfectly from its JSON representation, but the resulting JSON output is very verbose. Apart from environments, all standard storage types are supported.

serializeJSON(x, digits = 8, pretty = FALSE)




an R object to be serialized


max number of digits (after the dot) to print for numeric values


add indentation/whitespace to JSON output. See prettify


a JSON string which was created using serializeJSON


JSON is a text based format which leads to loss of precision when printing numbers.


jsoncars <- serializeJSON(mtcars) mtcars2 <- unserializeJSON(jsoncars) identical(mtcars, mtcars2)
#> [1] TRUE
set.seed('123') myobject <- list( mynull = NULL, mycomplex = lapply(eigen(matrix(-rnorm(9),3)), round, 3), mymatrix = round(matrix(rnorm(9), 3),3), myint = as.integer(c(1,2,3)), mydf = cars, mylist = list(foo='bar', 123, NA, NULL, list('test')), mylogical = c(TRUE,FALSE,NA), mychar = c('foo', NA, 'bar'), somemissings = c(1,2,NA,NaN,5, Inf, 7 -Inf, 9, NA), myrawvec = charToRaw('This is a test') ); identical(unserializeJSON(serializeJSON(myobject)), myobject);
#> [1] TRUE