diff --git a/internal/service/cluster_service.go b/internal/service/cluster_service.go
index 3d1cdfa..3cd9426 100644
--- a/internal/service/cluster_service.go
+++ b/internal/service/cluster_service.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"strconv"
+	"time"
 
 	"gcy_hpc_server/internal/model"
 	"gcy_hpc_server/internal/slurm"
@@ -55,11 +56,30 @@ func NewClusterService(client *slurm.Client, logger *zap.Logger) *ClusterService
 }
 
 func (s *ClusterService) GetNodes(ctx context.Context) ([]model.NodeResponse, error) {
+	s.logger.Debug("slurm API request",
+		zap.String("operation", "GetNodes"),
+	)
+
+	start := time.Now()
 	resp, _, err := s.client.Nodes.GetNodes(ctx, nil)
+	took := time.Since(start)
+
 	if err != nil {
+		s.logger.Debug("slurm API error response",
+			zap.String("operation", "GetNodes"),
+			zap.Duration("took", took),
+			zap.Error(err),
+		)
 		s.logger.Error("failed to get nodes", zap.Error(err))
 		return nil, fmt.Errorf("get nodes: %w", err)
 	}
+
+	s.logger.Debug("slurm API response",
+		zap.String("operation", "GetNodes"),
+		zap.Duration("took", took),
+		zap.Any("body", resp),
+	)
+
 	if resp.Nodes == nil {
 		return nil, nil
 	}
@@ -71,11 +91,33 @@ func (s *ClusterService) GetNodes(ctx context.Context) ([]model.NodeResponse, er
 }
 
 func (s *ClusterService) GetNode(ctx context.Context, name string) (*model.NodeResponse, error) {
+	s.logger.Debug("slurm API request",
+		zap.String("operation", "GetNode"),
+		zap.String("node_name", name),
+	)
+
+	start := time.Now()
 	resp, _, err := s.client.Nodes.GetNode(ctx, name, nil)
+	took := time.Since(start)
+
 	if err != nil {
+		s.logger.Debug("slurm API error response",
+			zap.String("operation", "GetNode"),
+			zap.String("node_name", name),
+			zap.Duration("took", took),
+			zap.Error(err),
+		)
 		s.logger.Error("failed to get node", zap.String("name", name), zap.Error(err))
 		return nil, fmt.Errorf("get node %s: %w", name, err)
 	}
+
+	s.logger.Debug("slurm API response",
+		zap.String("operation", "GetNode"),
+		zap.String("node_name", name),
+		zap.Duration("took", took),
+		zap.Any("body", resp),
+	)
+
 	if resp.Nodes == nil || len(*resp.Nodes) == 0 {
 		return nil, nil
 	}
@@ -85,11 +127,30 @@ func (s *ClusterService) GetNode(ctx context.Context, name string) (*model.NodeR
 }
 
 func (s *ClusterService) GetPartitions(ctx context.Context) ([]model.PartitionResponse, error) {
+	s.logger.Debug("slurm API request",
+		zap.String("operation", "GetPartitions"),
+	)
+
+	start := time.Now()
 	resp, _, err := s.client.Partitions.GetPartitions(ctx, nil)
+	took := time.Since(start)
+
 	if err != nil {
+		s.logger.Debug("slurm API error response",
+			zap.String("operation", "GetPartitions"),
+			zap.Duration("took", took),
+			zap.Error(err),
+		)
 		s.logger.Error("failed to get partitions", zap.Error(err))
 		return nil, fmt.Errorf("get partitions: %w", err)
 	}
+
+	s.logger.Debug("slurm API response",
+		zap.String("operation", "GetPartitions"),
+		zap.Duration("took", took),
+		zap.Any("body", resp),
+	)
+
 	if resp.Partitions == nil {
 		return nil, nil
 	}
@@ -101,11 +162,33 @@ func (s *ClusterService) GetPartitions(ctx context.Context) ([]model.PartitionRe
 }
 
 func (s *ClusterService) GetPartition(ctx context.Context, name string) (*model.PartitionResponse, error) {
+	s.logger.Debug("slurm API request",
+		zap.String("operation", "GetPartition"),
+		zap.String("partition_name", name),
+	)
+
+	start := time.Now()
 	resp, _, err := s.client.Partitions.GetPartition(ctx, name, nil)
+	took := time.Since(start)
+
 	if err != nil {
+		s.logger.Debug("slurm API error response",
+			zap.String("operation", "GetPartition"),
+			zap.String("partition_name", name),
+			zap.Duration("took", took),
+			zap.Error(err),
+		)
 		s.logger.Error("failed to get partition", zap.String("name", name), zap.Error(err))
 		return nil, fmt.Errorf("get partition %s: %w", name, err)
 	}
+
+	s.logger.Debug("slurm API response",
+		zap.String("operation", "GetPartition"),
+		zap.String("partition_name", name),
+		zap.Duration("took", took),
+		zap.Any("body", resp),
+	)
+
 	if resp.Partitions == nil || len(*resp.Partitions) == 0 {
 		return nil, nil
 	}
@@ -115,11 +198,30 @@ func (s *ClusterService) GetPartition(ctx context.Context, name string) (*model.
 }
 
 func (s *ClusterService) GetDiag(ctx context.Context) (*slurm.OpenapiDiagResp, error) {
+	s.logger.Debug("slurm API request",
+		zap.String("operation", "GetDiag"),
+	)
+
+	start := time.Now()
 	resp, _, err := s.client.Diag.GetDiag(ctx)
+	took := time.Since(start)
+
 	if err != nil {
+		s.logger.Debug("slurm API error response",
+			zap.String("operation", "GetDiag"),
+			zap.Duration("took", took),
+			zap.Error(err),
+		)
 		s.logger.Error("failed to get diag", zap.Error(err))
 		return nil, fmt.Errorf("get diag: %w", err)
 	}
+
+	s.logger.Debug("slurm API response",
+		zap.String("operation", "GetDiag"),
+		zap.Duration("took", took),
+		zap.Any("body", resp),
+	)
+
 	return resp, nil
 }
 
diff --git a/internal/service/job_service.go b/internal/service/job_service.go
index 636ee99..fe5067f 100644
--- a/internal/service/job_service.go
+++ b/internal/service/job_service.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"strconv"
+	"time"
 
 	"gcy_hpc_server/internal/model"
 	"gcy_hpc_server/internal/slurm"
@@ -45,12 +46,31 @@ func (s *JobService) SubmitJob(ctx context.Context, req *model.SubmitJobRequest)
 		Job:    jobDesc,
 	}
 
+	s.logger.Debug("slurm API request",
+		zap.String("operation", "SubmitJob"),
+		zap.Any("body", submitReq),
+	)
+
+	start := time.Now()
 	result, _, err := s.client.Jobs.SubmitJob(ctx, submitReq)
+	took := time.Since(start)
+
 	if err != nil {
+		s.logger.Debug("slurm API error response",
+			zap.String("operation", "SubmitJob"),
+			zap.Duration("took", took),
+			zap.Error(err),
+		)
 		s.logger.Error("failed to submit job", zap.Error(err), zap.String("operation", "submit"))
 		return nil, fmt.Errorf("submit job: %w", err)
 	}
 
+	s.logger.Debug("slurm API response",
+		zap.String("operation", "SubmitJob"),
+		zap.Duration("took", took),
+		zap.Any("body", result),
+	)
+
 	resp := &model.JobResponse{}
 	if result.Result != nil && result.Result.JobID != nil {
 		resp.JobID = *result.Result.JobID
@@ -64,12 +84,31 @@ func (s *JobService) SubmitJob(ctx context.Context, req *model.SubmitJobRequest)
 
 // GetJobs lists all current jobs from Slurm.
 func (s *JobService) GetJobs(ctx context.Context) ([]model.JobResponse, error) {
+	s.logger.Debug("slurm API request",
+		zap.String("operation", "GetJobs"),
+	)
+
+	start := time.Now()
 	result, _, err := s.client.Jobs.GetJobs(ctx, nil)
+	took := time.Since(start)
+
 	if err != nil {
+		s.logger.Debug("slurm API error response",
+			zap.String("operation", "GetJobs"),
+			zap.Duration("took", took),
+			zap.Error(err),
+		)
 		s.logger.Error("failed to get jobs", zap.Error(err), zap.String("operation", "get_jobs"))
 		return nil, fmt.Errorf("get jobs: %w", err)
 	}
 
+	s.logger.Debug("slurm API response",
+		zap.String("operation", "GetJobs"),
+		zap.Duration("took", took),
+		zap.Int("job_count", len(result.Jobs)),
+		zap.Any("body", result),
+	)
+
 	jobs := make([]model.JobResponse, 0, len(result.Jobs))
 	for i := range result.Jobs {
 		jobs = append(jobs, mapJobInfo(&result.Jobs[i]))
@@ -79,12 +118,33 @@ func (s *JobService) GetJobs(ctx context.Context) ([]model.JobResponse, error) {
 
 // GetJob retrieves a single job by ID.
 func (s *JobService) GetJob(ctx context.Context, jobID string) (*model.JobResponse, error) {
+	s.logger.Debug("slurm API request",
+		zap.String("operation", "GetJob"),
+		zap.String("job_id", jobID),
+	)
+
+	start := time.Now()
 	result, _, err := s.client.Jobs.GetJob(ctx, jobID, nil)
+	took := time.Since(start)
+
 	if err != nil {
+		s.logger.Debug("slurm API error response",
+			zap.String("operation", "GetJob"),
+			zap.String("job_id", jobID),
+			zap.Duration("took", took),
+			zap.Error(err),
+		)
 		s.logger.Error("failed to get job", zap.Error(err), zap.String("job_id", jobID), zap.String("operation", "get_job"))
 		return nil, fmt.Errorf("get job %s: %w", jobID, err)
 	}
 
+	s.logger.Debug("slurm API response",
+		zap.String("operation", "GetJob"),
+		zap.String("job_id", jobID),
+		zap.Duration("took", took),
+		zap.Any("body", result),
+	)
+
 	if len(result.Jobs) == 0 {
 		return nil, nil
 	}
@@ -95,11 +155,32 @@ func (s *JobService) GetJob(ctx context.Context, jobID string) (*model.JobRespon
 
 // CancelJob cancels a job by ID.
 func (s *JobService) CancelJob(ctx context.Context, jobID string) error {
-	_, _, err := s.client.Jobs.DeleteJob(ctx, jobID, nil)
+	s.logger.Debug("slurm API request",
+		zap.String("operation", "CancelJob"),
+		zap.String("job_id", jobID),
+	)
+
+	start := time.Now()
+	result, _, err := s.client.Jobs.DeleteJob(ctx, jobID, nil)
+	took := time.Since(start)
+
 	if err != nil {
+		s.logger.Debug("slurm API error response",
+			zap.String("operation", "CancelJob"),
+			zap.String("job_id", jobID),
+			zap.Duration("took", took),
+			zap.Error(err),
+		)
 		s.logger.Error("failed to cancel job", zap.Error(err), zap.String("job_id", jobID), zap.String("operation", "cancel"))
 		return fmt.Errorf("cancel job %s: %w", jobID, err)
 	}
+
+	s.logger.Debug("slurm API response",
+		zap.String("operation", "CancelJob"),
+		zap.String("job_id", jobID),
+		zap.Duration("took", took),
+		zap.Any("body", result),
+	)
 	s.logger.Info("job cancelled", zap.String("job_id", jobID))
 	return nil
 }
@@ -129,12 +210,32 @@ func (s *JobService) GetJobHistory(ctx context.Context, query *model.JobHistoryQ
 		opts.EndTime = strToPtr(query.EndTime)
 	}
 
+	s.logger.Debug("slurm API request",
+		zap.String("operation", "GetJobHistory"),
+		zap.Any("body", opts),
+	)
+
+	start := time.Now()
 	result, _, err := s.client.SlurmdbJobs.GetJobs(ctx, opts)
+	took := time.Since(start)
+
 	if err != nil {
+		s.logger.Debug("slurm API error response",
+			zap.String("operation", "GetJobHistory"),
+			zap.Duration("took", took),
+			zap.Error(err),
+		)
 		s.logger.Error("failed to get job history", zap.Error(err), zap.String("operation", "get_job_history"))
 		return nil, fmt.Errorf("get job history: %w", err)
 	}
 
+	s.logger.Debug("slurm API response",
+		zap.String("operation", "GetJobHistory"),
+		zap.Duration("took", took),
+		zap.Int("job_count", len(result.Jobs)),
+		zap.Any("body", result),
+	)
+
 	allJobs := make([]model.JobResponse, 0, len(result.Jobs))
 	for i := range result.Jobs {
 		allJobs = append(allJobs, mapSlurmdbJob(&result.Jobs[i]))
@@ -150,17 +251,17 @@ func (s *JobService) GetJobHistory(ctx context.Context, query *model.JobHistoryQ
 		pageSize = 20
 	}
 
-	start := (page - 1) * pageSize
-	end := start + pageSize
-	if start > total {
-		start = total
+	startIdx := (page - 1) * pageSize
+	end := startIdx + pageSize
+	if startIdx > total {
+		startIdx = total
 	}
 	if end > total {
 		end = total
 	}
 
 	return &model.JobListResponse{
-		Jobs:     allJobs[start:end],
+		Jobs:     allJobs[startIdx:end],
 		Total:    total,
 		Page:     page,
 		PageSize: pageSize,