diff --git a/DESCRIPTION b/DESCRIPTION
index e7ddbd6..81c2b68 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: yyjsonr
 Type: Package
 Title: Fast JSON Parser and Generator 
-Version: 0.1.18
+Version: 0.1.18.9000
 Authors@R: c(
     person("Mike", "Cheng", role = c("aut", "cre", 'cph'), 
     email = "mikefc@coolbutuseless.com"),
diff --git a/NEWS.md b/NEWS.md
index 3e3774a..e440a71 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,15 @@
 
 
+# yyjsonr 0.1.18.9000 2024-01-25
+
+* New `fast_numerics` flag when writing.
+    * Default `FALSE`
+    * If `TRUE` the user is guaranteeing that there are no NA, NaN or Inf values
+      in the numeric and integer vectors, and thus a faster method for writing
+      these vectors to JSON can be used.
+* Changed writing of `raw` vectors to always use the `fast_numerics` method,
+  as raw R vectors (by definition) will not have NA, NaN or Inf values.
+
 # yyjsonr 0.1.18 2024-01-22
 
 * Fixes for CRAN
diff --git a/R/json-opts.R b/R/json-opts.R
index ebc4f05..120a1d7 100644
--- a/R/json-opts.R
+++ b/R/json-opts.R
@@ -256,6 +256,15 @@ opts_read_json <- function(
 #' @param num_specials Should special numeric values (i.e. NA, NaN, Inf) be
 #'        converted to a JSON \code{null} value or converted to a string 
 #'        representation e.g. "NA"/"NaN" etc.   Default: 'null'
+#' @param fast_numerics Does the user guarantee that there are no NA, NaN or Inf
+#'        values in the numeric vectors?  Default: FALSE.  If \code{TRUE} then
+#'        numeric and integer vectors will be written to JSON using a faster method.
+#'        Note: if there are NA, NaN or Inf values, an error will be thrown.
+#'        Expert users are invited to also consider the
+#'        \code{YYJSON_WRITE_ALLOW_INF_AND_NAN} and 
+#'        \code{YYJSON_WRITE_INF_AND_NAN_AS_NULL} options for \code{yyjson_write_flags}
+#'        and should consult the \code{yyjson} API documentation for 
+#'        further details.
 #' @param yyjson_write_flag integer vector corresponding to internal \code{yyjson}
 #'        options.  See \code{yyjson_write_flag} in this package, and read
 #'        the yyjson API documentation for more information.  This is considered
@@ -277,6 +286,7 @@ opts_write_json <- function(
     name_repair       = c('none', 'minimal'),
     num_specials      = c('null', 'string'),
     str_specials      = c('null', 'string'),
+    fast_numerics     = FALSE,
     yyjson_write_flag = 0L) {
   
   structure(
@@ -289,6 +299,7 @@ opts_write_json <- function(
       name_repair       = match.arg(name_repair),
       str_specials      = match.arg(str_specials),
       num_specials      = match.arg(num_specials),
+      fast_numerics     = isTRUE(fast_numerics),
       yyjson_write_flag = as.integer(yyjson_write_flag)
     ),
     class = "opts_write_json"
diff --git a/man/opts_write_json.Rd b/man/opts_write_json.Rd
index 2533b90..ec15ed5 100644
--- a/man/opts_write_json.Rd
+++ b/man/opts_write_json.Rd
@@ -13,6 +13,7 @@ opts_write_json(
   name_repair = c("none", "minimal"),
   num_specials = c("null", "string"),
   str_specials = c("null", "string"),
+  fast_numerics = FALSE,
   yyjson_write_flag = 0L
 )
 }
@@ -48,6 +49,16 @@ representation e.g. "NA"/"NaN" etc.   Default: 'null'}
 be converted to a
 JSON \code{null} value, or converted to a string "NA"?  Default: 'null'}
 
+\item{fast_numerics}{Does the user guarantee that there are no NA, NaN or Inf
+values in the numeric vectors?  Default: FALSE.  If \code{TRUE} then
+numeric and integer vectors will be written to JSON using a faster method.
+Note: if there are NA, NaN or Inf values, an error will be thrown.
+Expert users are invited to also consider the
+\code{YYJSON_WRITE_ALLOW_INF_AND_NAN} and
+\code{YYJSON_WRITE_INF_AND_NAN_AS_NULL} options for \code{yyjson_write_flags}
+and should consult the \code{yyjson} API documentation for
+further details.}
+
 \item{yyjson_write_flag}{integer vector corresponding to internal \code{yyjson}
 options.  See \code{yyjson_write_flag} in this package, and read
 the yyjson API documentation for more information.  This is considered
diff --git a/src/R-yyjson-serialize.c b/src/R-yyjson-serialize.c
index c4c6acd..fbdc831 100644
--- a/src/R-yyjson-serialize.c
+++ b/src/R-yyjson-serialize.c
@@ -36,6 +36,7 @@ serialize_options parse_serialize_options(SEXP serialize_opts_) {
     .name_repair       = NAME_REPAIR_NONE,
     .num_specials      = NUM_SPECIALS_AS_NULL,
     .str_specials      = STR_SPECIALS_AS_NULL,
+    .fast_numerics     = FALSE,
     .yyjson_write_flag = 0,
   };
   
@@ -85,6 +86,8 @@ serialize_options parse_serialize_options(SEXP serialize_opts_) {
     } else if (strcmp(opt_name, "num_specials") == 0) {
       const char *val = CHAR(STRING_ELT(val_, 0));
       opt.num_specials = strcmp(val, "string") == 0 ? NUM_SPECIALS_AS_STRING : NUM_SPECIALS_AS_NULL;
+    } else if (strcmp(opt_name, "fast_numerics") == 0) {
+      opt.fast_numerics = asLogical(val_);
     } else {
       warning("Unknown option ignored: '%s'\n", opt_name);
     }
@@ -390,14 +393,9 @@ yyjson_mut_val *vector_factor_to_json_array(SEXP vec_, yyjson_mut_doc *doc, seri
 //===========================================================================
 yyjson_mut_val *vector_rawsxp_to_json_array(SEXP vec_, yyjson_mut_doc *doc, serialize_options *opt) {
   
-  yyjson_mut_val *arr = yyjson_mut_arr(doc);
-  
-  unsigned char *ptr = RAW(vec_);
-  for (int i = 0; i < length(vec_); i++) {
-    yyjson_mut_arr_append(arr, yyjson_mut_uint(doc, *ptr++));
-  }
   
-  return arr;
+  // Raw vectors can't have NA, so can use the fast method
+  return yyjson_mut_arr_with_uint8(doc, RAW(vec_), (size_t)length(vec_));
 }
 
 
@@ -455,16 +453,19 @@ yyjson_mut_val *vector_intsxp_to_json_array(SEXP vec_, yyjson_mut_doc *doc, seri
     return vector_date_to_json_array(vec_, doc, opt);
   } else if (inherits(vec_, "POSIXct")) {
     return vector_posixct_to_json_array(vec_, doc, opt);
-  } 
-  
-  yyjson_mut_val *arr = yyjson_mut_arr(doc);
-  
-  int32_t *ptr = INTEGER(vec_);
-  for (int i = 0; i < length(vec_); i++) {
-    yyjson_mut_arr_append(arr, scalar_integer_to_json_val(*ptr++, doc, opt));
+  } else if (opt->fast_numerics) {
+    return yyjson_mut_arr_with_sint32(doc, INTEGER(vec_), (size_t)length(vec_));
+  } else {
+    
+    yyjson_mut_val *arr = yyjson_mut_arr(doc);
+    
+    int32_t *ptr = INTEGER(vec_);
+    for (int i = 0; i < length(vec_); i++) {
+      yyjson_mut_arr_append(arr, scalar_integer_to_json_val(*ptr++, doc, opt));
+    }
+    
+    return arr;
   }
-  
-  return arr;
 }
 
 
@@ -480,17 +481,19 @@ yyjson_mut_val *vector_realsxp_to_json_array(SEXP vec_, yyjson_mut_doc *doc, ser
     return vector_posixct_to_json_array(vec_, doc, opt);
   } else if (inherits(vec_, "integer64")) {
     return vector_integer64_to_json_array(vec_, doc, opt);
+  } else if (opt->fast_numerics) {
+    return yyjson_mut_arr_with_double(doc, REAL(vec_), (size_t)length(vec_));
+  } else {
+    
+    yyjson_mut_val *arr = yyjson_mut_arr(doc);
+    
+    double *ptr = REAL(vec_);
+    for (int i = 0; i < length(vec_); i++) {
+      yyjson_mut_arr_append(arr, scalar_double_to_json_val(*ptr++, doc, opt));
+    }
+    
+    return arr;
   }
-  
-  
-  yyjson_mut_val *arr = yyjson_mut_arr(doc);
-  
-  double *ptr = REAL(vec_);
-  for (int i = 0; i < length(vec_); i++) {
-    yyjson_mut_arr_append(arr, scalar_double_to_json_val(*ptr++, doc, opt));
-  }
-  
-  return arr;
 }
 
 
diff --git a/src/R-yyjson-serialize.h b/src/R-yyjson-serialize.h
index 262d6e7..7c6beef 100644
--- a/src/R-yyjson-serialize.h
+++ b/src/R-yyjson-serialize.h
@@ -75,6 +75,7 @@ typedef struct {
   unsigned int str_specials;
   unsigned int num_specials;
   unsigned int yyjson_write_flag;
+  bool fast_numerics;
 } serialize_options;
 
 //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/tests/testthat/test-fast-numerics.R b/tests/testthat/test-fast-numerics.R
new file mode 100644
index 0000000..328903e
--- /dev/null
+++ b/tests/testthat/test-fast-numerics.R
@@ -0,0 +1,12 @@
+
+test_that("fast-numerics works", {
+  expect_equal(
+    write_json_str(mtcars, dataframe = 'columns', fast_numerics = FALSE),
+    write_json_str(mtcars, dataframe = 'columns', fast_numerics =  TRUE)
+  )
+  
+  expect_equal(
+    write_json_str(iris, dataframe = 'columns', fast_numerics = FALSE),
+    write_json_str(iris, dataframe = 'columns', fast_numerics =  TRUE)
+  )
+})