diff --git a/flagengine/utils/time.go b/flagengine/utils/time.go
index 767dc27..2df0920 100644
--- a/flagengine/utils/time.go
+++ b/flagengine/utils/time.go
@@ -3,19 +3,19 @@ package utils
 import (
 	"strings"
 	"time"
-)
 
-const iso8601 = "2006-01-02T15:04:05.999999"
+	"github.com/nav-inc/datetime"
+)
 
 type ISOTime struct {
 	time.Time
 }
 
 func (i *ISOTime) UnmarshalJSON(bytes []byte) (err error) {
-	i.Time, err = time.Parse(iso8601, strings.Trim(string(bytes), `"`))
+	i.Time, err = datetime.Parse(strings.Trim(string(bytes), `"`), time.UTC)
 	return
 }
 
 func (i *ISOTime) MarshalJSON() ([]byte, error) {
-	return []byte(`"` + i.Time.Format(iso8601) + `"`), nil
+	return []byte(`"` + i.Time.Format(time.RFC3339) + `"`), nil
 }
diff --git a/go.mod b/go.mod
index d77ec71..8d6eaab 100644
--- a/go.mod
+++ b/go.mod
@@ -11,6 +11,7 @@ require (
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/nav-inc/datetime v0.1.3 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
diff --git a/go.sum b/go.sum
index d6a6d46..fc854ff 100644
--- a/go.sum
+++ b/go.sum
@@ -1,11 +1,15 @@
 github.com/blang/semver/v4 v4.0.0 h1:1PFHFE6yCCTv8C1TeyNNarDzntLi7wMI5i/pzqYIsAM=
 github.com/blang/semver/v4 v4.0.0/go.mod h1:IbckMUScFkM3pff0VJDNKRiT6TG/YpiHIM2yvyW5YoQ=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/nav-inc/datetime v0.1.3 h1:PaybPUsScX+Cd3TEa1tYpfwU61deCEhMTlCO2hONm1c=
+github.com/nav-inc/datetime v0.1.3/go.mod h1:gKGf5G+cW7qkTo5TC/sieNyz6lYdrA9cf1PNV+pXIOE=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.2.1/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 golang.org/x/exp v0.0.0-20230713183714-613f0c0eb8a1 h1:MGwJjxBy0HJshjDNfLsYO8xppfqWlA5ZT9OhtUUhTNw=