diff --git a/differential.go b/differential.go
index 43db9ac..c6ee924 100644
--- a/differential.go
+++ b/differential.go
@@ -56,3 +56,13 @@ func (c *Conn) DifferentialRevisionEdit(req requests.EditRequest) (*responses.Ed
 
 	return &res, nil
 }
+
+// DifferentialGetRawDiff performs a call to differential.getrawdiff
+func (c *Conn) DifferentialGetRawDiff(req requests.DifferentialGetRawDiffRequest) (*responses.DifferentialGetRawDiffResponse, error) {
+	var res responses.DifferentialGetRawDiffResponse
+	if err := c.Call("differential.getrawdiff", &req, &res); err != nil {
+		return nil, err
+	}
+
+	return &res, nil
+}
diff --git a/entities/differential.go b/entities/differential.go
index ce44475..a8e8824 100644
--- a/entities/differential.go
+++ b/entities/differential.go
@@ -69,6 +69,10 @@ type DifferentialHunk struct {
 	Corpus    string `json:"corpus"`
 }
 
+// A DifferentialRawDiff is a raw diff.
+type DifferentialRawDiff struct {
+	Diff string `json:"diff"`
+}
 
 // DifferentialDiffUpdateTransaction adds a diff (by PHID) to the given revision
 func DifferentialDiffUpdateTransaction(diff PHID) Transaction {
@@ -324,4 +328,4 @@ func DifferentialSetSubscribersTransaction(subscribers []PHID) Transaction {
 		Type:  "subscribers.set",
 		Value: subscribers,
 	}
-}
\ No newline at end of file
+}
diff --git a/requests/differential_getrawdiff.go b/requests/differential_getrawdiff.go
new file mode 100644
index 0000000..45034b1
--- /dev/null
+++ b/requests/differential_getrawdiff.go
@@ -0,0 +1,7 @@
+package requests
+
+// DifferentialGetRawDiffRequest represents a request to differential.getrawdiff.
+type DifferentialGetRawDiffRequest struct {
+	DiffID string `json:"diffID"`
+	Request
+}
diff --git a/responses/differential_getrawdiff.go b/responses/differential_getrawdiff.go
new file mode 100644
index 0000000..1af2223
--- /dev/null
+++ b/responses/differential_getrawdiff.go
@@ -0,0 +1,6 @@
+package responses
+
+import "github.com/thought-machine/gonduit/entities"
+
+// DifferentialGetRawDiffResponse is the response from calling differential.getrawdiff.
+type DifferentialGetRawDiffResponse *entities.DifferentialRawDiff
diff --git a/test/server/server.go b/test/server/server.go
index 18ff3a1..96c3c5f 100644
--- a/test/server/server.go
+++ b/test/server/server.go
@@ -32,10 +32,10 @@ func New() *Server {
 func (s *Server) RegisterCapabilities() {
 	s.RegisterMethod("conduit.getcapabilities", 200, gin.H{
 		"result": map[string][]string{
-			"authentication": []string{"token", "session"},
-			"signatures":     []string{"consign"},
-			"input":          []string{"json", "urlencoded"},
-			"output":         []string{"json"},
+			"authentication": {"token", "session"},
+			"signatures":     {"consign"},
+			"input":          {"json", "urlencoded"},
+			"output":         {"json"},
 		},
 	})
 }