diff --git a/apps/api/internal/domains/email/campaign_service_test.go b/apps/api/internal/domains/email/campaign_service_test.go
new file mode 100644
index 00000000..d1a309b8
--- /dev/null
+++ b/apps/api/internal/domains/email/campaign_service_test.go
@@ -0,0 +1,139 @@
+package email
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/swamphacks/core/apps/api/internal/database/sqlc"
+)
+
+func TestValidateCampaignContent(t *testing.T) {
+	tests := []struct {
+		name           string
+		title          string
+		subject        string
+		body           string
+		recipientTypes []string
+		expectedError  error
+	}{
+		{
+			name:           "valid campaign",
+			title:          "Welcome",
+			subject:        "Welcome to SwampHacks",
+			body:           "Campaign body",
+			recipientTypes: []string{"admins"},
+			expectedError:  nil,
+		},
+		{
+			name:           "missing title",
+			title:          "   ",
+			subject:        "Subject",
+			body:           "Body",
+			recipientTypes: []string{"admins"},
+			expectedError:  ErrEmailCampaignTitleRequired,
+		},
+		{
+			name:           "missing subject",
+			title:          "Title",
+			subject:        "",
+			body:           "Body",
+			recipientTypes: []string{"admins"},
+			expectedError:  ErrEmailCampaignSubjectRequired,
+		},
+		{
+			name:           "missing body",
+			title:          "Title",
+			subject:        "Subject",
+			body:           "   ",
+			recipientTypes: []string{"admins"},
+			expectedError:  ErrEmailCampaignBodyRequired,
+		},
+		{
+			name:           "missing recipients",
+			title:          "Title",
+			subject:        "Subject",
+			body:           "Body",
+			recipientTypes: nil,
+			expectedError:  ErrEmailCampaignRecipientsRequired,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			err := validateCampaignContent(
+				test.title,
+				test.subject,
+				test.body,
+				test.recipientTypes,
+			)
+
+			if !errors.Is(err, test.expectedError) {
+				t.Fatalf("expected error %v, got %v", test.expectedError, err)
+			}
+		})
+	}
+}
+
+func TestCanEditCampaign(t *testing.T) {
+	tests := []struct {
+		status   sqlc.EmailCampaignStatus
+		expected bool
+	}{
+		{status: sqlc.EmailCampaignStatusDraft, expected: true},
+		{status: sqlc.EmailCampaignStatusScheduled, expected: true},
+		{status: sqlc.EmailCampaignStatusSending, expected: false},
+		{status: sqlc.EmailCampaignStatusSent, expected: false},
+		{status: sqlc.EmailCampaignStatusFailed, expected: false},
+	}
+
+	for _, test := range tests {
+		t.Run(string(test.status), func(t *testing.T) {
+			result := canEditCampaign(test.status)
+
+			if result != test.expected {
+				t.Fatalf("expected %v, got %v", test.expected, result)
+			}
+		})
+	}
+}
+
+func TestUpdateCampaignStatusRequiresScheduledAt(t *testing.T) {
+	service := &EmailCampaignService{}
+
+	_, err := service.UpdateCampaignStatus(
+		context.Background(),
+		sqlc.UpdateEmailCampaignStatusParams{
+			Status:      sqlc.EmailCampaignStatusScheduled,
+			ScheduledAt: nil,
+		},
+	)
+
+	if !errors.Is(err, ErrEmailCampaignScheduledAtRequired) {
+		t.Fatalf(
+			"expected %v, got %v",
+			ErrEmailCampaignScheduledAtRequired,
+			err,
+		)
+	}
+}
+
+func TestUpdateCampaignStatusRequiresSentAt(t *testing.T) {
+	service := &EmailCampaignService{}
+
+	_, err := service.UpdateCampaignStatus(
+		context.Background(),
+		sqlc.UpdateEmailCampaignStatusParams{
+			Status: sqlc.EmailCampaignStatusSent,
+			SentAt: nil,
+		},
+	)
+
+	if !errors.Is(err, ErrEmailCampaignSentAtRequired) {
+		t.Fatalf(
+			"expected %v, got %v",
+			ErrEmailCampaignSentAtRequired,
+			err,
+		)
+	}
+}
\ No newline at end of file