diff --git a/cli/internal/cmd/sign.go b/cli/internal/cmd/sign.go
index 5b045e0..f9d0d43 100644
--- a/cli/internal/cmd/sign.go
+++ b/cli/internal/cmd/sign.go
@@ -2,13 +2,14 @@ package cmd
 
 import (
 	"encoding/base64"
-	"encoding/hex"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"os"
 
 	"github.com/randa-mu/ssv-dkg/cli"
 	"github.com/randa-mu/ssv-dkg/shared"
+	"github.com/randa-mu/ssv-dkg/shared/api"
 	"github.com/spf13/cobra"
 )
 
@@ -44,15 +45,17 @@ func Sign(cmd *cobra.Command, _ []string) {
 	}
 
 	log := shared.QuietLogger{Quiet: shortFlag}
-	signingOutput, err := cli.Sign(shared.Uniq(append(args, operatorFlag...)), depositData, log)
+	// TODO: this should probably sign something more than just the deposit data root
+	signingOutput, err := cli.Sign(shared.Uniq(append(args, operatorFlag...)), depositData.DepositDataRoot, log)
 	if err != nil {
 		shared.Exit(fmt.Sprintf("%v", err))
 	}
 
-	log.MaybeLog(fmt.Sprintf("✅ received signed deposit data! sessionID: %s", hex.EncodeToString(signingOutput.SessionID)))
+	path := cli.CreateFilename(stateDirectory, signingOutput)
+
+	log.MaybeLog(fmt.Sprintf("✅ received signed deposit data! stored state in %s", path))
 	log.Log(base64.StdEncoding.EncodeToString(signingOutput.GroupSignature))
 
-	path := cli.CreateFilename(stateDirectory, signingOutput)
 	bytes, err := cli.StoreStateIfNotExists(path, signingOutput)
 	if err != nil {
 		log.Log(fmt.Sprintf("⚠️  there was an error storing the state; you should store it somewhere for resharing. Error: %v", err))
@@ -60,25 +63,31 @@ func Sign(cmd *cobra.Command, _ []string) {
 	}
 }
 
-func verifyAndGetArgs(cmd *cobra.Command) ([]string, []byte, error) {
+func verifyAndGetArgs(cmd *cobra.Command) ([]string, api.UnsignedDepositData, error) {
 	// if the operator flag isn't passed, we consume operator addresses from stdin
 	operators, err := arrayOrReader(operatorFlag, cmd.InOrStdin())
 	if err != nil {
-		return nil, nil, errors.New("you must provider either the --operator flag or operators via stdin")
+		return nil, api.UnsignedDepositData{}, errors.New("you must provider either the --operator flag or operators via stdin")
 	}
 
 	if inputPathFlag == "" {
-		return nil, nil, errors.New("input path cannot be empty")
+		return nil, api.UnsignedDepositData{}, errors.New("input path cannot be empty")
 	}
 
 	// there is a default value, so this shouldn't really happen
 	if stateDirectory == "" {
-		return nil, nil, errors.New("you must provide a state directory")
+		return nil, api.UnsignedDepositData{}, errors.New("you must provide a state directory")
+	}
+
+	depositBytes, err := os.ReadFile(inputPathFlag)
+	if err != nil {
+		return nil, api.UnsignedDepositData{}, fmt.Errorf("error reading the deposit data file: %v", err)
 	}
 
-	depositData, err := os.ReadFile(inputPathFlag)
+	var depositData api.UnsignedDepositData
+	err = json.Unmarshal(depositBytes, &depositData)
 	if err != nil {
-		return nil, nil, fmt.Errorf("error reading the deposit data file: %v", err)
+		return nil, api.UnsignedDepositData{}, err
 	}
 
 	return operators, depositData, nil
diff --git a/cli/internal/cmd/sign_test.go b/cli/internal/cmd/sign_test.go
index 56a7720..a5eba13 100644
--- a/cli/internal/cmd/sign_test.go
+++ b/cli/internal/cmd/sign_test.go
@@ -1,18 +1,21 @@
 package cmd
 
 import (
+	"encoding/json"
+	"math/big"
 	"os"
 	"path"
 	"strings"
 	"testing"
 
+	"github.com/randa-mu/ssv-dkg/shared/api"
 	"github.com/stretchr/testify/require"
 )
 
 func TestSignCommand(t *testing.T) {
 	tmp := t.TempDir()
 	filepath := path.Join(tmp, "testfile")
-	createJunkFile(t, filepath)
+	createdUnsignedDepositData(t, filepath)
 
 	tests := []struct {
 		name        string
@@ -96,10 +99,22 @@ func TestSignCommand(t *testing.T) {
 	}
 }
 
-func createJunkFile(t *testing.T, filepath string) {
+func createdUnsignedDepositData(t *testing.T, filepath string) {
+	data := api.UnsignedDepositData{
+		WithdrawalCredentials: []byte("hello world"),
+		DepositDataRoot:       []byte("hello world"),
+		DepositMessageRoot:    []byte("hello world"),
+		Amount:                api.BigInt{Int: *big.NewInt(1)},
+		ForkVersion:           "somefork",
+		NetworkName:           "somenetwork",
+		DepositCLIVersion:     "somecli",
+	}
+
+	bytes, err := json.Marshal(data)
+	require.NoError(t, err)
 	file, err := os.Create(filepath)
 	require.NoError(t, err)
-	_, err = file.Write([]byte("hello"))
+	_, err = file.Write(bytes)
 	require.NoError(t, err)
 	err = file.Close()
 	require.NoError(t, err)
diff --git a/shared/api/cli.go b/shared/api/cli.go
index df0b112..b55c33b 100644
--- a/shared/api/cli.go
+++ b/shared/api/cli.go
@@ -1,6 +1,27 @@
 package api
 
-import "github.com/randa-mu/ssv-dkg/shared/crypto"
+import (
+	"fmt"
+	"math/big"
+
+	"github.com/randa-mu/ssv-dkg/shared/crypto"
+)
+
+type UnsignedDepositData struct {
+	WithdrawalCredentials []byte `json:"withdrawal_credentials"`
+	DepositDataRoot       []byte `json:"deposit_data_root"`
+	DepositMessageRoot    []byte `json:"deposit_message_root,omitempty"`
+	Amount                BigInt `json:"amount,omitempty"`
+	ForkVersion           string `json:"fork_version,omitempty"`
+	NetworkName           string `json:"network_name,omitempty"`
+	DepositCLIVersion     string `json:"deposit_cli_version,omitempty"`
+}
+
+type SignedDepositData struct {
+	UnsignedDepositData
+	PubKey    []byte `json:"pubkey"`
+	Signature []byte `json:"signature"`
+}
 
 type SigningOutput struct {
 	SessionID             []byte          `json:"session_id"`
@@ -18,3 +39,25 @@ type OperatorResponse struct {
 	Identity crypto.Identity
 	Response SignResponse
 }
+
+type BigInt struct {
+	big.Int
+}
+
+// MarshalJSON intentionally uses a value pointer or things go wrong
+func (b BigInt) MarshalJSON() ([]byte, error) {
+	return []byte(b.String()), nil
+}
+
+func (b *BigInt) UnmarshalJSON(p []byte) error {
+	if string(p) == "null" {
+		return nil
+	}
+	var z big.Int
+	_, ok := z.SetString(string(p), 10)
+	if !ok {
+		return fmt.Errorf("not a valid big integer: %s", p)
+	}
+	b.Int = z
+	return nil
+}