diff --git a/cmd/uncloud/context/ls.go b/cmd/uncloud/context/ls.go
index e9eb4b98..d2b74b8c 100644
--- a/cmd/uncloud/context/ls.go
+++ b/cmd/uncloud/context/ls.go
@@ -1,34 +1,58 @@
 package context
 
 import (
+	"encoding/json"
 	"fmt"
 	"maps"
 	"slices"
 
 	"github.com/psviderski/uncloud/internal/cli"
+	"github.com/psviderski/uncloud/internal/cli/config"
+	"github.com/psviderski/uncloud/internal/cli/output"
 	"github.com/psviderski/uncloud/internal/cli/tui"
 	"github.com/spf13/cobra"
 )
 
+type listOptions struct {
+	output string
+}
+
 func NewListCommand() *cobra.Command {
+	opts := listOptions{}
+
 	cmd := &cobra.Command{
 		Use:     "ls",
 		Aliases: []string{"list"},
 		Short:   "List available cluster contexts.",
+		Args:    cobra.NoArgs,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			uncli := cmd.Context().Value("cli").(*cli.CLI)
-			return list(uncli)
+			return list(uncli, opts)
+		},
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			return output.FlagValue(opts.output)
 		},
 	}
 
+	output.Flag(cmd, &opts.output)
+
 	return cmd
 }
 
-func list(uncli *cli.CLI) error {
+func list(uncli *cli.CLI, opts listOptions) error {
 	if uncli.Config == nil {
 		return fmt.Errorf("context management is not available: Uncloud configuration file is not being used")
 	}
 
+	if opts.output == "json" {
+		type Contexts struct { // Wrap in Contexts type to create array of Contexts.
+			Contexts map[string]*config.Context `json:"Contexts"`
+		}
+		data, _ := json.MarshalIndent(Contexts{uncli.Config.Contexts}, "", "  ")
+		fmt.Println(string(data))
+		return nil
+	}
+
 	if len(uncli.Config.Contexts) == 0 {
 		fmt.Println("No contexts found")
 		return nil
diff --git a/cmd/uncloud/image/ls.go b/cmd/uncloud/image/ls.go
index 324a7e08..3cfc35c4 100644
--- a/cmd/uncloud/image/ls.go
+++ b/cmd/uncloud/image/ls.go
@@ -2,6 +2,7 @@ package image
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"os"
 	"slices"
@@ -17,6 +18,7 @@ import (
 
 	"github.com/psviderski/uncloud/internal/cli"
 	"github.com/psviderski/uncloud/internal/cli/completion"
+	"github.com/psviderski/uncloud/internal/cli/output"
 	"github.com/psviderski/uncloud/internal/cli/tui"
 	"github.com/psviderski/uncloud/pkg/api"
 	"github.com/spf13/cobra"
@@ -25,6 +27,7 @@ import (
 type listOptions struct {
 	machines   []string
 	nameFilter string
+	output     string
 }
 
 func NewListCommand() *cobra.Command {
@@ -57,11 +60,15 @@ func NewListCommand() *cobra.Command {
 			uncli := cmd.Context().Value("cli").(*cli.CLI)
 			return list(cmd.Context(), uncli, opts)
 		},
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			return output.FlagValue(opts.output)
+		},
 	}
 
 	cmd.Flags().StringSliceVarP(&opts.machines, "machine", "m", nil,
 		"Filter images by machine name or ID. Can be specified multiple times or as a comma-separated list. "+
 			"(default is include all machines)")
+	output.Flag(cmd, &opts.output)
 
 	completion.MachinesFlag(cmd)
 
@@ -114,6 +121,12 @@ func list(ctx context.Context, uncli *cli.CLI, opts listOptions) error {
 	// Collect all images from all machines.
 	var rows []imageRow
 
+	// Wrapper struct for json output.
+	type Images struct {
+		Images []image.Summary
+	}
+	images := Images{Images: []image.Summary{}}
+
 	for _, machineImages := range clusterImages {
 		// Get machine name for better readability.
 		machineName := machineImages.Metadata.Machine
@@ -126,6 +139,11 @@ func list(ctx context.Context, uncli *cli.CLI, opts listOptions) error {
 			store = "containerd"
 		}
 
+		if opts.output == "json" {
+			images.Images = append(images.Images, machineImages.Images...)
+			continue
+		}
+
 		// Process each image for this machine.
 		for _, img := range machineImages.Images {
 			// Show the first 12 chars without 'sha256:' as the image ID like Docker does.
@@ -171,6 +189,12 @@ func list(ctx context.Context, uncli *cli.CLI, opts listOptions) error {
 		}
 	}
 
+	if opts.output == "json" {
+		data, _ := json.MarshalIndent(images, "", "  ")
+		fmt.Println(string(data))
+		return nil
+	}
+
 	if len(rows) == 0 {
 		if opts.nameFilter != "" {
 			fmt.Printf("No images matching '%s' found.\n", opts.nameFilter)
diff --git a/cmd/uncloud/machine/ls.go b/cmd/uncloud/machine/ls.go
index e04c15d8..db46541b 100644
--- a/cmd/uncloud/machine/ls.go
+++ b/cmd/uncloud/machine/ls.go
@@ -2,30 +2,46 @@ package machine
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"net/netip"
 	"strings"
 
 	"github.com/psviderski/uncloud/internal/cli"
+	"github.com/psviderski/uncloud/internal/cli/output"
 	"github.com/psviderski/uncloud/internal/cli/tui"
 	"github.com/psviderski/uncloud/internal/machine/network"
+	"github.com/psviderski/uncloud/pkg/api"
 	"github.com/spf13/cobra"
 )
 
+type listOptions struct {
+	output string
+}
+
 func NewListCommand() *cobra.Command {
+	opts := listOptions{}
+
 	cmd := &cobra.Command{
 		Use:     "ls",
 		Aliases: []string{"list"},
 		Short:   "List machines in a cluster.",
+		Args:    cobra.NoArgs,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			uncli := cmd.Context().Value("cli").(*cli.CLI)
-			return list(cmd.Context(), uncli)
+			return list(cmd.Context(), uncli, opts)
+		},
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			return output.FlagValue(opts.output)
 		},
 	}
+
+	output.Flag(cmd, &opts.output)
+
 	return cmd
 }
 
-func list(ctx context.Context, uncli *cli.CLI) error {
+func list(ctx context.Context, uncli *cli.CLI, opts listOptions) error {
 	client, err := uncli.ConnectCluster(ctx)
 	if err != nil {
 		return fmt.Errorf("connect to cluster: %w", err)
@@ -37,6 +53,16 @@ func list(ctx context.Context, uncli *cli.CLI) error {
 		return fmt.Errorf("list machines: %w", err)
 	}
 
+	if opts.output == "json" {
+		// Wrap in Machines type to create array of Machines.
+		type Machines struct {
+			Machines api.MachineMembersList `json:"Machines"`
+		}
+		data, _ := json.MarshalIndent(Machines{machines}, "", "  ")
+		fmt.Println(string(data))
+		return nil
+	}
+
 	// Print the list of machines in a table format.
 	t := tui.NewTable()
 	t.Headers("NAME", "STATE", "ADDRESS", "PUBLIC IP", "WIREGUARD ENDPOINTS", "MACHINE ID")
diff --git a/cmd/uncloud/volume/ls.go b/cmd/uncloud/volume/ls.go
index e6b6d343..d8d19ac1 100644
--- a/cmd/uncloud/volume/ls.go
+++ b/cmd/uncloud/volume/ls.go
@@ -2,12 +2,14 @@ package volume
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"slices"
 	"strings"
 
 	"github.com/psviderski/uncloud/internal/cli"
 	"github.com/psviderski/uncloud/internal/cli/completion"
+	"github.com/psviderski/uncloud/internal/cli/output"
 	"github.com/psviderski/uncloud/internal/cli/tui"
 	"github.com/psviderski/uncloud/pkg/api"
 	"github.com/spf13/cobra"
@@ -16,6 +18,7 @@ import (
 type listOptions struct {
 	machines []string
 	quiet    bool
+	output   string
 }
 
 func NewListCommand() *cobra.Command {
@@ -25,10 +28,14 @@ func NewListCommand() *cobra.Command {
 		Use:     "ls",
 		Aliases: []string{"list"},
 		Short:   "List volumes across all machines in the cluster.",
+		Args:    cobra.NoArgs,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			uncli := cmd.Context().Value("cli").(*cli.CLI)
 			return list(cmd.Context(), uncli, opts)
 		},
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			return output.FlagValue(opts.output)
+		},
 	}
 
 	cmd.Flags().StringSliceVarP(&opts.machines, "machine", "m", nil,
@@ -36,6 +43,7 @@ func NewListCommand() *cobra.Command {
 			"(default is include all machines)")
 	cmd.Flags().BoolVarP(&opts.quiet, "quiet", "q", false,
 		"Only display volume names.")
+	output.Flag(cmd, &opts.output)
 
 	completion.MachinesFlag(cmd)
 
@@ -63,6 +71,15 @@ func list(ctx context.Context, uncli *cli.CLI, opts listOptions) error {
 		return fmt.Errorf("list volumes: %w", err)
 	}
 
+	if opts.output == "json" {
+		type Volumes struct { // Wrap in Volumes type to create array of Volumes.
+			Volumes []api.MachineVolume `json:"Volumes"`
+		}
+		data, _ := json.MarshalIndent(Volumes{volumes}, "", "  ")
+		fmt.Println(string(data))
+		return nil
+	}
+
 	if len(volumes) == 0 {
 		if !opts.quiet {
 			fmt.Println("No volumes found.")
diff --git a/internal/cli/config/config.go b/internal/cli/config/config.go
index 34548767..697b4ca3 100644
--- a/internal/cli/config/config.go
+++ b/internal/cli/config/config.go
@@ -9,8 +9,8 @@ import (
 )
 
 type Config struct {
-	CurrentContext string              `yaml:"current_context"`
-	Contexts       map[string]*Context `yaml:"contexts"`
+	CurrentContext string              `yaml:"current_context" json:"CurrentContext"`
+	Contexts       map[string]*Context `yaml:"contexts" json:"Contexts"`
 
 	// path is the file path config is read from.
 	path string
diff --git a/internal/cli/config/connection.go b/internal/cli/config/connection.go
index 4762be99..19f3fe5c 100644
--- a/internal/cli/config/connection.go
+++ b/internal/cli/config/connection.go
@@ -13,20 +13,20 @@ import (
 
 type MachineConnection struct {
 	// SSH uses the system ssh CLI command to connect. This is the default SSH connection method.
-	SSH SSHDestination `yaml:"ssh,omitempty"`
+	SSH SSHDestination `yaml:"ssh,omitempty" json:"SSH,omitempty"`
 	// SSHCLI is a backward-compatible alias for SSH.
-	SSHCLI SSHDestination `yaml:"ssh_cli,omitempty"`
+	SSHCLI SSHDestination `yaml:"ssh_cli,omitempty" json:"SSHCli,omitempty"`
 	// SSHGo uses Go's built-in SSH library to connect.
-	SSHGo      SSHDestination `yaml:"ssh_go,omitempty"`
-	SSHKeyFile string         `yaml:"ssh_key_file,omitempty"`
+	SSHGo      SSHDestination `yaml:"ssh_go,omitempty" json:"SSHGo,omitempty"`
+	SSHKeyFile string         `yaml:"ssh_key_file,omitempty" json:"SSHKey,omitempty"`
 	// TCP is the address and port of the machine's API server.
 	// The pointer is used to omit the field when not set. Otherwise, yaml marshalling includes an empty object.
-	TCP *netip.AddrPort `yaml:"tcp,omitempty"`
+	TCP *netip.AddrPort `yaml:"tcp,omitempty" json:"TCP,omitempty"`
 	// Unix is the path to the machine's API unix socket.
-	Unix      string        `yaml:"unix,omitempty"`
-	Host      string        `yaml:"host,omitempty"`
-	PublicKey secret.Secret `yaml:"public_key,omitempty"`
-	MachineID string        `yaml:"machine_id,omitempty"`
+	Unix      string        `yaml:"unix,omitempty" json:"Unix,omitempty"`
+	Host      string        `yaml:"host,omitempty" json:"Host,omitempty"`
+	PublicKey secret.Secret `yaml:"public_key,omitempty" json:"PublicKey,omitempty"`
+	MachineID string        `yaml:"machine_id,omitempty" json:"MachineID,omitempty"`
 }
 
 func (c *MachineConnection) String() string {
diff --git a/internal/cli/config/context.go b/internal/cli/config/context.go
index 60ca8043..5bc8ff41 100644
--- a/internal/cli/config/context.go
+++ b/internal/cli/config/context.go
@@ -1,8 +1,8 @@
 package config
 
 type Context struct {
-	Name        string              `yaml:"-"`
-	Connections []MachineConnection `yaml:"connections"`
+	Name        string              `yaml:"-" json:"-"`
+	Connections []MachineConnection `yaml:"connections" json:"Connections"`
 }
 
 func (c *Context) SetDefaultConnection(index int) {
diff --git a/internal/cli/output/output.go b/internal/cli/output/output.go
new file mode 100644
index 00000000..87826f09
--- /dev/null
+++ b/internal/cli/output/output.go
@@ -0,0 +1,22 @@
+package output
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+func Flag(cmd *cobra.Command, value *string) {
+	cmd.Flags().StringVarP(value, "output", "o", "",
+		"Output format. Currently only 'json' is supported.")
+}
+
+func FlagValue(value string) error {
+	switch value {
+	case "json":
+		return nil
+	case "":
+		return nil
+	}
+	return fmt.Errorf("invalid --output format, want 'json'")
+}
diff --git a/internal/machine/api/pb/common.go b/internal/machine/api/pb/common.go
index 8eea6fad..bba7c288 100644
--- a/internal/machine/api/pb/common.go
+++ b/internal/machine/api/pb/common.go
@@ -27,6 +27,14 @@ func (ip *IP) Equal(other *IP) bool {
 	return bytes.Equal(ip.Ip, other.Ip)
 }
 
+func (ip *IP) MarshalJSON() ([]byte, error) {
+	if ip == nil {
+		return nil, nil
+	}
+	addr, _ := ip.ToAddr()
+	return []byte("\"" + addr.String() + "\""), nil
+}
+
 func NewIPPort(ap netip.AddrPort) *IPPort {
 	return &IPPort{Ip: NewIP(ap.Addr()), Port: uint32(ap.Port())}
 }
@@ -39,6 +47,14 @@ func (ipp *IPPort) ToAddrPort() (netip.AddrPort, error) {
 	return netip.AddrPortFrom(addr, uint16(ipp.Port)), nil
 }
 
+func (ipp *IPPort) MarshalJSON() ([]byte, error) {
+	if ipp == nil {
+		return nil, nil
+	}
+	addrPort, _ := ipp.ToAddrPort()
+	return []byte("\"" + addrPort.String() + "\""), nil
+}
+
 func NewIPPrefix(p netip.Prefix) *IPPrefix {
 	return &IPPrefix{Ip: NewIP(p.Addr()), Bits: uint32(p.Bits())}
 }
diff --git a/website/docs/9-cli-reference/uc_ctx_ls.md b/website/docs/9-cli-reference/uc_ctx_ls.md
index 63569dfe..d9897476 100644
--- a/website/docs/9-cli-reference/uc_ctx_ls.md
+++ b/website/docs/9-cli-reference/uc_ctx_ls.md
@@ -9,7 +9,8 @@ uc ctx ls [flags]
 ## Options
 
 ```
-  -h, --help   help for ls
+  -h, --help            help for ls
+  -o, --output string   Output format. Currently only 'json' is supported.
 ```
 
 ## Options inherited from parent commands
diff --git a/website/docs/9-cli-reference/uc_image_ls.md b/website/docs/9-cli-reference/uc_image_ls.md
index 701149d3..a8c37e62 100644
--- a/website/docs/9-cli-reference/uc_image_ls.md
+++ b/website/docs/9-cli-reference/uc_image_ls.md
@@ -34,6 +34,7 @@ uc image ls [REPO:[TAG]] [flags]
 ```
   -h, --help              help for ls
   -m, --machine strings   Filter images by machine name or ID. Can be specified multiple times or as a comma-separated list. (default is include all machines)
+  -o, --output string     Output format. Currently only 'json' is supported.
 ```
 
 ## Options inherited from parent commands
diff --git a/website/docs/9-cli-reference/uc_images.md b/website/docs/9-cli-reference/uc_images.md
index aaf173c3..7158073e 100644
--- a/website/docs/9-cli-reference/uc_images.md
+++ b/website/docs/9-cli-reference/uc_images.md
@@ -34,6 +34,7 @@ uc images [IMAGE] [flags]
 ```
   -h, --help              help for images
   -m, --machine strings   Filter images by machine name or ID. Can be specified multiple times or as a comma-separated list. (default is include all machines)
+  -o, --output string     Output format. Currently only 'json' is supported.
 ```
 
 ## Options inherited from parent commands
diff --git a/website/docs/9-cli-reference/uc_machine_ls.md b/website/docs/9-cli-reference/uc_machine_ls.md
index 37ae0b18..8d5bf2ee 100644
--- a/website/docs/9-cli-reference/uc_machine_ls.md
+++ b/website/docs/9-cli-reference/uc_machine_ls.md
@@ -9,7 +9,8 @@ uc machine ls [flags]
 ## Options
 
 ```
-  -h, --help   help for ls
+  -h, --help            help for ls
+  -o, --output string   Output format. Currently only 'json' is supported.
 ```
 
 ## Options inherited from parent commands
diff --git a/website/docs/9-cli-reference/uc_volume_ls.md b/website/docs/9-cli-reference/uc_volume_ls.md
index a1123dc3..693abf2f 100644
--- a/website/docs/9-cli-reference/uc_volume_ls.md
+++ b/website/docs/9-cli-reference/uc_volume_ls.md
@@ -11,6 +11,7 @@ uc volume ls [flags]
 ```
   -h, --help              help for ls
   -m, --machine strings   Filter volumes by machine name or ID. Can be specified multiple times or as a comma-separated list. (default is include all machines)
+  -o, --output string     Output format. Currently only 'json' is supported.
   -q, --quiet             Only display volume names.
 ```