diff --git a/internal/dorkly/flag.go b/internal/dorkly/flag.go
index 3967009..1ce4e52 100644
--- a/internal/dorkly/flag.go
+++ b/internal/dorkly/flag.go
@@ -2,6 +2,7 @@ package dorkly
 
 import (
 	"encoding/base64"
+	"errors"
 	"github.com/launchdarkly/go-sdk-common/v3/ldvalue"
 	"github.com/launchdarkly/go-server-sdk-evaluation/v3/ldmodel"
 )
@@ -30,22 +31,58 @@ const (
 // when combined with a FlagBase, it can be converted to a LaunchDarkly FeatureFlag
 type FlagConfigForEnv interface {
 	ToLdFlag(flagBase FlagBase) ldmodel.FeatureFlag
+	Validate(flagBase FlagBase) error
 }
 
+var _ FlagConfigForEnv = &FlagBoolean{}
+
 // FlagBoolean is a boolean flag that is either on (true) or off (false)
 type FlagBoolean struct {
 	Variation bool `yaml:"variation"`
 }
 
+func (f *FlagBoolean) Validate(flagBase FlagBase) error {
+	return nil
+}
+
 func (f *FlagBoolean) ToLdFlag(flagBase FlagBase) ldmodel.FeatureFlag {
 	return flagBase.ldFeatureFlagBoolean(f.Variation)
 }
 
+var _ FlagConfigForEnv = &FlagBooleanRollout{}
+
 // FlagBooleanRollout is a boolean flag that is on (true) for a percentage of users based on the id field
 type FlagBooleanRollout struct {
 	PercentRollout BooleanRolloutVariation `yaml:"percentRollout"`
 }
 
+func (f *FlagBooleanRollout) Validate(flagBase FlagBase) error {
+	if f.PercentRollout.True < 0.0 {
+		return errors.New("percentRollout.true must be >= 0")
+	}
+	if f.PercentRollout.False < 0.0 {
+		return errors.New("percentRollout.false must be >= 0")
+	}
+
+	if f.PercentRollout.True+f.PercentRollout.False > 100 {
+		return errors.New("sum of percentRollout values must be <= 100")
+	}
+
+	if f.PercentRollout.True == 0.0 && f.PercentRollout.False == 0 {
+		return errors.New("at least one of percentRollout.true or percentRollout.false must be > 0")
+	}
+
+	if f.PercentRollout.True == 0.0 {
+		f.PercentRollout.True = 100.0 - f.PercentRollout.False
+	}
+
+	if f.PercentRollout.False == 0.0 {
+		f.PercentRollout.False = 100.0 - f.PercentRollout.True
+	}
+
+	return nil
+}
+
 type BooleanRolloutVariation struct {
 	True  float64 `yaml:"true"`
 	False float64 `yaml:"false"`
diff --git a/internal/dorkly/flag_test.go b/internal/dorkly/flag_test.go
index b205121..db3523d 100644
--- a/internal/dorkly/flag_test.go
+++ b/internal/dorkly/flag_test.go
@@ -7,6 +7,117 @@ import (
 	"testing"
 )
 
+func TestFlagBooleanRollout_Validate(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    FlagBooleanRollout
+		expected *FlagBooleanRollout
+		wantErr  bool
+	}{
+		{
+			name: "ValidPercentages",
+			input: FlagBooleanRollout{
+				PercentRollout: BooleanRolloutVariation{
+					True:  30.0,
+					False: 70.0,
+				},
+			},
+			expected: &FlagBooleanRollout{
+				PercentRollout: BooleanRolloutVariation{
+					True:  30.0,
+					False: 70.0,
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "ValidTruePercentage",
+			input: FlagBooleanRollout{
+				PercentRollout: BooleanRolloutVariation{
+					True: 30.0,
+				},
+			},
+			expected: &FlagBooleanRollout{
+				PercentRollout: BooleanRolloutVariation{
+					True:  30.0,
+					False: 70.0,
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "ValidFalsePercentage",
+			input: FlagBooleanRollout{
+				PercentRollout: BooleanRolloutVariation{
+					False: 70.0,
+				},
+			},
+			expected: &FlagBooleanRollout{
+				PercentRollout: BooleanRolloutVariation{
+					True:  30.0,
+					False: 70.0,
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "NegativeTruePercentage",
+			input: FlagBooleanRollout{
+				PercentRollout: BooleanRolloutVariation{
+					True:  -10.0,
+					False: 70.0,
+				},
+			},
+			expected: nil,
+			wantErr:  true,
+		},
+		{
+			name: "NegativeFalsePercentage",
+			input: FlagBooleanRollout{
+				PercentRollout: BooleanRolloutVariation{
+					True:  30.0,
+					False: -10.0,
+				},
+			},
+			expected: nil,
+			wantErr:  true,
+		},
+		{
+			name: "SumGreaterThan100",
+			input: FlagBooleanRollout{
+				PercentRollout: BooleanRolloutVariation{
+					True:  60.0,
+					False: 50.0,
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "BothPercentagesZero",
+			input: FlagBooleanRollout{
+				PercentRollout: BooleanRolloutVariation{
+					True:  0.0,
+					False: 0.0,
+				},
+			},
+			expected: nil,
+			wantErr:  true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := tt.input.Validate(FlagBase{})
+			if tt.wantErr {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.expected, &tt.input)
+			}
+		})
+	}
+}
+
 func Test_FlagBoolean_ToLdFlag(t *testing.T) {
 	cases := []struct {
 		name     string
diff --git a/internal/dorkly/project.go b/internal/dorkly/project.go
index b07e130..7afd16b 100644
--- a/internal/dorkly/project.go
+++ b/internal/dorkly/project.go
@@ -110,10 +110,16 @@ func (p *Project) loadFlagYamlFile(filePath string) (*Flag, error) {
 	flag.key = getFileNameNoSuffix(f.Name())
 	flag.envConfigs = make(map[string]FlagConfigForEnv)
 	for _, env := range p.environments {
-		flag.envConfigs[env], err = p.loadFlagConfigForEnvYamlFile(flag, filepath.Join(p.path, "environments", env, flag.key+".yml"))
+		flagEnvConfig, err := p.loadFlagConfigForEnvYamlFile(flag, filepath.Join(p.path, "environments", env, flag.key+".yml"))
 		if err != nil {
 			return nil, err
 		}
+		err = flagEnvConfig.Validate(flag.FlagBase)
+		if err != nil {
+			return nil, err
+		}
+		flag.envConfigs[env] = flagEnvConfig
+
 	}
 
 	return &flag, nil
diff --git a/internal/dorkly/project_test.go b/internal/dorkly/project_test.go
index e06bcee..c8b023a 100644
--- a/internal/dorkly/project_test.go
+++ b/internal/dorkly/project_test.go
@@ -38,8 +38,8 @@ var (
 					EnableMobileKey: true,
 				},
 				envConfigs: map[string]FlagConfigForEnv{
-					"production": &FlagBooleanRollout{PercentRollout: 31.0},
-					"staging":    &FlagBooleanRollout{PercentRollout: 100.0},
+					"production": &FlagBooleanRollout{PercentRollout: BooleanRolloutVariation{True: 31.0, False: 69.0}},
+					"staging":    &FlagBooleanRollout{PercentRollout: BooleanRolloutVariation{True: 100.0, False: 0.0}},
 				},
 			},
 		},
diff --git a/internal/dorkly/testdata/testProject1/inputYaml/environments/production/rollout1.yml b/internal/dorkly/testdata/testProject1/inputYaml/environments/production/rollout1.yml
index 4f09d2d..43a007c 100644
--- a/internal/dorkly/testdata/testProject1/inputYaml/environments/production/rollout1.yml
+++ b/internal/dorkly/testdata/testProject1/inputYaml/environments/production/rollout1.yml
@@ -1,3 +1,2 @@
 percentRollout:
-  true: 31.0
-  false: 69.0
\ No newline at end of file
+  true: 31.0
\ No newline at end of file
diff --git a/internal/dorkly/testdata/testProject1/inputYaml/environments/staging/rollout1.yml b/internal/dorkly/testdata/testProject1/inputYaml/environments/staging/rollout1.yml
index 6585f4d..98f48ce 100644
--- a/internal/dorkly/testdata/testProject1/inputYaml/environments/staging/rollout1.yml
+++ b/internal/dorkly/testdata/testProject1/inputYaml/environments/staging/rollout1.yml
@@ -1,3 +1,2 @@
 percentRollout:
-  true: 100.0
-  false: 0.0
\ No newline at end of file
+  true: 100.0
\ No newline at end of file