diff --git a/docs/spec/components/schemas/Link.yaml b/docs/spec/components/schemas/Link.yaml
index c7d0d9d..f28d6c5 100644
--- a/docs/spec/components/schemas/Link.yaml
+++ b/docs/spec/components/schemas/Link.yaml
@@ -16,5 +16,6 @@ allOf:
             example: '05260b49-2c35-48b9-8300-d39ae48ca312'
           created_at:
             type: string
-            description: The date and time when the proof was created in the timestamp format
-            example: '1702480643'
+            format: time.Time
+            description: The date and time when the proof was created in the RFC3339 format
+            example: "2021-08-12T12:00:00Z"
diff --git a/docs/spec/components/schemas/Proof.yaml b/docs/spec/components/schemas/Proof.yaml
index b09e99e..09c7d96 100644
--- a/docs/spec/components/schemas/Proof.yaml
+++ b/docs/spec/components/schemas/Proof.yaml
@@ -12,14 +12,16 @@ allOf:
           - proof
           - proof_type
           - org_id
+          - schema_url
         properties:
           creator:
             type: string
             description: The ID of the user who created the proof
           created_at:
             type: string
-            description: The date and time when the proof was created in the timestamp format
-            example: '1702480643'
+            format: time.Time
+            description: The date and time when the proof was created in the RFC3339 format
+            example: "2021-08-12T12:00:00Z"
           proof:
             type: string
             description: The proof object in JSON string format
@@ -30,3 +32,6 @@ allOf:
           org_id:
             type: string
             description: The ID of the organization that issued the proof's claim
+          schema_url:
+            type: string
+            description: The schema URL of the claim the proof was created based on
diff --git a/docs/spec/components/schemas/ProofCreate.yaml b/docs/spec/components/schemas/ProofCreate.yaml
index 5afb079..f2f7218 100644
--- a/docs/spec/components/schemas/ProofCreate.yaml
+++ b/docs/spec/components/schemas/ProofCreate.yaml
@@ -3,6 +3,7 @@ required:
   - proof
   - proof_type
   - org_id
+  - schema_url
 properties:
   proof:
     type: string
@@ -14,3 +15,6 @@ properties:
   org_id:
     type: string
     description: The ID of the organization that issued the proof's claim
+  schema_url:
+    type: string
+    description: The schema URL of the claim the proof was created based on
diff --git a/internal/assets/migrations/002_proof_schema.sql b/internal/assets/migrations/002_proof_schema.sql
new file mode 100644
index 0000000..0dd53cf
--- /dev/null
+++ b/internal/assets/migrations/002_proof_schema.sql
@@ -0,0 +1,5 @@
+-- +migrate Up
+alter table proofs add column schema_url text not null default '';
+
+-- +migrate Down
+alter table proofs drop column schema_url;
diff --git a/internal/data/main.go b/internal/data/main.go
index 8de91f6..045735d 100644
--- a/internal/data/main.go
+++ b/internal/data/main.go
@@ -6,8 +6,8 @@ import (
 	"github.com/google/uuid"
 )
 
-//go:generate xo schema "postgres://link:link@localhost:15432/link-db?sslmode=disable" -o ./ --single=schema.xo.go --src templates
-//go:generate xo schema "postgres://link:link@localhost:15432/link-db?sslmode=disable" -o pg --single=schema.xo.go --src=pg/templates --go-context=both
+//go:generate xo schema "postgres://link:link@localhost:25432/link-db?sslmode=disable" -o ./ --single=schema.xo.go --src templates
+//go:generate xo schema "postgres://link:link@localhost:25432/link-db?sslmode=disable" -o pg --single=schema.xo.go --src=pg/templates --go-context=both
 //go:generate goimports -w ./
 
 type Storage interface {
diff --git a/internal/data/pg/schema.xo.go b/internal/data/pg/schema.xo.go
index 96f7968..04a535d 100644
--- a/internal/data/pg/schema.xo.go
+++ b/internal/data/pg/schema.xo.go
@@ -292,18 +292,18 @@ func (s Storage) ProofQ() data.ProofQ {
 	return NewProofQ(s.DB())
 }
 
-var colsProof = `id, creator, created_at, proof, org_id, type`
+var colsProof = `id, creator, created_at, proof, org_id, type, schema_url`
 
 // InsertCtx inserts a Proof to the database.
 func (q ProofQ) InsertCtx(ctx context.Context, p *data.Proof) error {
 	// sql insert query, primary key must be provided
 	sqlstr := `INSERT INTO public.proofs (` +
-		`id, creator, created_at, proof, org_id, type` +
+		`id, creator, created_at, proof, org_id, type, schema_url` +
 		`) VALUES (` +
-		`$1, $2, $3, $4, $5, $6` +
+		`$1, $2, $3, $4, $5, $6, $7` +
 		`)`
 	// run
-	err := q.db.ExecRawContext(ctx, sqlstr, p.ID, p.Creator, p.CreatedAt, p.Proof, p.OrgID, p.Type)
+	err := q.db.ExecRawContext(ctx, sqlstr, p.ID, p.Creator, p.CreatedAt, p.Proof, p.OrgID, p.Type, p.SchemaURL)
 	return errors.Wrap(err, "failed to execute insert query")
 }
 
@@ -316,10 +316,10 @@ func (q ProofQ) Insert(p *data.Proof) error {
 func (q ProofQ) UpdateCtx(ctx context.Context, p *data.Proof) error {
 	// update with composite primary key
 	sqlstr := `UPDATE public.proofs SET ` +
-		`creator = $1, proof = $2, org_id = $3, type = $4 ` +
-		`WHERE id = $5`
+		`creator = $1, proof = $2, org_id = $3, type = $4, schema_url = $5 ` +
+		`WHERE id = $6`
 	// run
-	err := q.db.ExecRawContext(ctx, sqlstr, p.Creator, p.Proof, p.OrgID, p.Type, p.ID)
+	err := q.db.ExecRawContext(ctx, sqlstr, p.Creator, p.Proof, p.OrgID, p.Type, p.SchemaURL, p.ID)
 	return errors.Wrap(err, "failed to execute update")
 }
 
@@ -332,15 +332,15 @@ func (q ProofQ) Update(p *data.Proof) error {
 func (q ProofQ) UpsertCtx(ctx context.Context, p *data.Proof) error {
 	// upsert
 	sqlstr := `INSERT INTO public.proofs (` +
-		`id, creator, created_at, proof, org_id, type` +
+		`id, creator, created_at, proof, org_id, type, schema_url` +
 		`) VALUES (` +
-		`$1, $2, $3, $4, $5, $6` +
+		`$1, $2, $3, $4, $5, $6, $7` +
 		`)` +
 		` ON CONFLICT (id) DO ` +
 		`UPDATE SET ` +
-		`creator = EXCLUDED.creator, proof = EXCLUDED.proof, org_id = EXCLUDED.org_id, type = EXCLUDED.type `
+		`creator = EXCLUDED.creator, proof = EXCLUDED.proof, org_id = EXCLUDED.org_id, type = EXCLUDED.type, schema_url = EXCLUDED.schema_url `
 	// run
-	if err := q.db.ExecRawContext(ctx, sqlstr, p.ID, p.Creator, p.CreatedAt, p.Proof, p.OrgID, p.Type); err != nil {
+	if err := q.db.ExecRawContext(ctx, sqlstr, p.ID, p.Creator, p.CreatedAt, p.Proof, p.OrgID, p.Type, p.SchemaURL); err != nil {
 		return errors.Wrap(err, "failed to execute upsert stmt")
 	}
 	return nil
@@ -473,7 +473,7 @@ func (q LinksToProofQ) LinksToProofByLinkIDProofID(linkID, proofID uuid.UUID, is
 func (q ProofQ) ProofByIDCtx(ctx context.Context, id uuid.UUID, isForUpdate bool) (*data.Proof, error) {
 	// query
 	sqlstr := `SELECT ` +
-		`id, creator, created_at, proof, org_id, type ` +
+		`id, creator, created_at, proof, org_id, type, schema_url ` +
 		`FROM public.proofs ` +
 		`WHERE id = $1`
 	// run
diff --git a/internal/data/schema.xo.go b/internal/data/schema.xo.go
index e7c81ca..070683a 100644
--- a/internal/data/schema.xo.go
+++ b/internal/data/schema.xo.go
@@ -94,5 +94,6 @@ type Proof struct {
 	Proof     xo.Jsonb  `db:"proof" json:"proof" structs:"proof"`                // proof
 	OrgID     uuid.UUID `db:"org_id" json:"org_id" structs:"org_id"`             // org_id
 	Type      string    `db:"type" json:"type" structs:"type"`                   // type
+	SchemaURL string    `db:"schema_url" json:"schema_url" structs:"schema_url"` // schema_url
 
 }
diff --git a/internal/services/api/handlers/create_proof.go b/internal/services/api/handlers/create_proof.go
index e00406e..d2060c7 100644
--- a/internal/services/api/handlers/create_proof.go
+++ b/internal/services/api/handlers/create_proof.go
@@ -2,6 +2,9 @@ package handlers
 
 import (
 	"encoding/json"
+	"net/http"
+	"time"
+
 	validation "github.com/go-ozzo/ozzo-validation/v4"
 	"github.com/google/uuid"
 	"github.com/rarimo/rarime-link-svc/internal/data"
@@ -9,9 +12,6 @@ import (
 	"gitlab.com/distributed_lab/ape"
 	"gitlab.com/distributed_lab/ape/problems"
 	"gitlab.com/distributed_lab/logan/v3/errors"
-	"net/http"
-	"strconv"
-	"time"
 )
 
 type proofCreateRequest struct {
@@ -40,8 +40,6 @@ func newProofCreateRequest(r *http.Request) (*proofCreateRequest, error) {
 	return &req, nil
 }
 
-// TODO add schema_url; change time format
-
 func CreateProof(w http.ResponseWriter, r *http.Request) {
 	req, err := newProofCreateRequest(r)
 	if err != nil {
@@ -62,6 +60,7 @@ func CreateProof(w http.ResponseWriter, r *http.Request) {
 		Proof:     []byte(req.Data.Proof),
 		Type:      req.Data.ProofType,
 		OrgID:     orgID,
+		SchemaURL: req.Data.SchemaUrl,
 	}
 
 	err = Storage(r).ProofQ().Insert(&proof)
@@ -78,11 +77,12 @@ func CreateProof(w http.ResponseWriter, r *http.Request) {
 				Type: resources.PROOFS,
 			},
 			Attributes: resources.ProofAttributes{
-				CreatedAt: strconv.FormatInt(proof.CreatedAt.Unix(), 10),
+				CreatedAt: proof.CreatedAt,
 				Creator:   proof.Creator,
 				Proof:     string(proof.Proof),
 				ProofType: proof.Type,
 				OrgId:     proof.OrgID.String(),
+				SchemaUrl: req.Data.SchemaUrl,
 			},
 		},
 		Included: resources.Included{},
diff --git a/internal/services/api/handlers/create_proof_link.go b/internal/services/api/handlers/create_proof_link.go
index 8ae3dc7..d80a4bf 100644
--- a/internal/services/api/handlers/create_proof_link.go
+++ b/internal/services/api/handlers/create_proof_link.go
@@ -92,7 +92,7 @@ func CreateProofLink(w http.ResponseWriter, r *http.Request) {
 			},
 			Attributes: resources.LinkAttributes{
 				Link:      linkID.String(),
-				CreatedAt: timestamp.String(),
+				CreatedAt: timestamp,
 			},
 		},
 		Included: resources.Included{},
diff --git a/internal/services/api/handlers/get_links_by_user.go b/internal/services/api/handlers/get_links_by_user.go
index 86bb0a3..3fda9ce 100644
--- a/internal/services/api/handlers/get_links_by_user.go
+++ b/internal/services/api/handlers/get_links_by_user.go
@@ -8,7 +8,6 @@ import (
 	"gitlab.com/distributed_lab/ape/problems"
 	"gitlab.com/distributed_lab/urlval"
 	"net/http"
-	"strconv"
 )
 
 type proofsLinksByUserDIDRequest struct {
@@ -55,7 +54,7 @@ func GetLinks(w http.ResponseWriter, r *http.Request) {
 					Type: resources.LINKS,
 				},
 				Attributes: resources.LinkAttributes{
-					CreatedAt: strconv.FormatInt(link.CreatedAt.Unix(), 10),
+					CreatedAt: link.CreatedAt,
 					Link:      link.ID.String(),
 				},
 			},
diff --git a/internal/services/api/handlers/get_proof.go b/internal/services/api/handlers/get_proof.go
index be518fe..b1e5b5b 100644
--- a/internal/services/api/handlers/get_proof.go
+++ b/internal/services/api/handlers/get_proof.go
@@ -9,7 +9,6 @@ import (
 	"gitlab.com/distributed_lab/ape/problems"
 	"gitlab.com/distributed_lab/logan/v3/errors"
 	"net/http"
-	"strconv"
 )
 
 type proofByIDRequest struct {
@@ -54,11 +53,12 @@ func ProofByID(w http.ResponseWriter, r *http.Request) {
 				Type: resources.PROOFS,
 			},
 			Attributes: resources.ProofAttributes{
-				CreatedAt: strconv.FormatInt(proof.CreatedAt.Unix(), 10),
+				CreatedAt: proof.CreatedAt,
 				Creator:   proof.Creator,
 				Proof:     string(proof.Proof),
 				ProofType: proof.Type,
 				OrgId:     proof.OrgID.String(),
+				SchemaUrl: proof.SchemaURL,
 			},
 		},
 		Included: resources.Included{},
diff --git a/internal/services/api/handlers/get_proofs_by_link.go b/internal/services/api/handlers/get_proofs_by_link.go
index 78e67a3..f4a3106 100644
--- a/internal/services/api/handlers/get_proofs_by_link.go
+++ b/internal/services/api/handlers/get_proofs_by_link.go
@@ -66,7 +66,7 @@ func GetLinkByID(w http.ResponseWriter, r *http.Request) {
 				Type: resources.LINKS,
 			},
 			Attributes: resources.LinkAttributes{
-				CreatedAt: link.CreatedAt.UTC().String(),
+				CreatedAt: link.CreatedAt,
 				Link:      link.ID.String(),
 			},
 		},
@@ -86,11 +86,12 @@ func GetLinkByID(w http.ResponseWriter, r *http.Request) {
 				Type: resources.PROOFS,
 			},
 			Attributes: resources.ProofAttributes{
-				CreatedAt: proof.CreatedAt.String(),
+				CreatedAt: proof.CreatedAt,
 				Creator:   proof.Creator,
 				Proof:     string(proof.Proof),
 				ProofType: proof.Type,
 				OrgId:     proof.OrgID.String(),
+				SchemaUrl: proof.SchemaURL,
 			},
 		})
 	}
diff --git a/internal/services/api/handlers/get_proofs_by_user.go b/internal/services/api/handlers/get_proofs_by_user.go
index 92c9b46..6cd05a5 100644
--- a/internal/services/api/handlers/get_proofs_by_user.go
+++ b/internal/services/api/handlers/get_proofs_by_user.go
@@ -1,14 +1,12 @@
 package handlers
 
 import (
-	"net/http"
-	"strconv"
-
 	validation "github.com/go-ozzo/ozzo-validation/v4"
 	"github.com/rarimo/rarime-link-svc/resources"
 	"gitlab.com/distributed_lab/ape"
 	"gitlab.com/distributed_lab/ape/problems"
 	"gitlab.com/distributed_lab/urlval"
+	"net/http"
 )
 
 type proofsByUserDIDRequest struct {
@@ -57,11 +55,12 @@ func GetProofs(w http.ResponseWriter, r *http.Request) {
 					Type: resources.PROOFS,
 				},
 				Attributes: resources.ProofAttributes{
-					CreatedAt: strconv.FormatInt(proof.CreatedAt.Unix(), 10),
+					CreatedAt: proof.CreatedAt,
 					Creator:   proof.Creator,
 					Proof:     string(proof.Proof),
 					ProofType: proof.Type,
 					OrgId:     proof.OrgID.String(),
+					SchemaUrl: proof.SchemaURL,
 				},
 			},
 		}
diff --git a/resources/model_link_attributes.go b/resources/model_link_attributes.go
index 90f4fd2..3049748 100644
--- a/resources/model_link_attributes.go
+++ b/resources/model_link_attributes.go
@@ -4,9 +4,11 @@
 
 package resources
 
+import "time"
+
 type LinkAttributes struct {
-	// The date and time when the proof was created in the timestamp format
-	CreatedAt string `json:"created_at"`
+	// The date and time when the proof was created in the RFC3339 format
+	CreatedAt time.Time `json:"created_at"`
 	// UUID Link to proofs
 	Link string `json:"link"`
 }
diff --git a/resources/model_proof_attributes.go b/resources/model_proof_attributes.go
index 39aa8dd..31ff939 100644
--- a/resources/model_proof_attributes.go
+++ b/resources/model_proof_attributes.go
@@ -4,9 +4,11 @@
 
 package resources
 
+import "time"
+
 type ProofAttributes struct {
-	// The date and time when the proof was created in the timestamp format
-	CreatedAt string `json:"created_at"`
+	// The date and time when the proof was created in the RFC3339 format
+	CreatedAt time.Time `json:"created_at"`
 	// The ID of the user who created the proof
 	Creator string `json:"creator"`
 	// The ID of the organization that issued the proof's claim
@@ -15,4 +17,6 @@ type ProofAttributes struct {
 	Proof string `json:"proof"`
 	// The type of the proof
 	ProofType string `json:"proof_type"`
+	// The schema URL of the claim the proof was created based on
+	SchemaUrl string `json:"schema_url"`
 }
diff --git a/resources/model_proof_create.go b/resources/model_proof_create.go
index 7dfa995..cce7254 100644
--- a/resources/model_proof_create.go
+++ b/resources/model_proof_create.go
@@ -11,4 +11,6 @@ type ProofCreate struct {
 	Proof string `json:"proof"`
 	// The type of the proof
 	ProofType string `json:"proof_type"`
+	// The schema URL of the claim the proof was created based on
+	SchemaUrl string `json:"schema_url"`
 }