diff --git a/internal/ops/ops.go b/internal/ops/ops.go
index fff43ad3..328fa184 100644
--- a/internal/ops/ops.go
+++ b/internal/ops/ops.go
@@ -19,6 +19,17 @@ type Ops struct {
 	data []byte
 	// refs hold external references for operations.
 	refs []interface{}
+	// stringRefs provides space for string references, pointers to which will
+	// be stored in refs. Storing a string directly in refs would cause a heap
+	// allocation, to store the string header in an interface value. The backing
+	// array of stringRefs, on the other hand, gets reused between calls to
+	// reset, making string references free on average.
+	//
+	// Appending to stringRefs might reallocate the backing array, which will
+	// leave pointers to the old array in refs. This temporarily causes a slight
+	// increase in memory usage, but this, too, amortizes away as the capacity
+	// of stringRefs approaches its stable maximum.
+	stringRefs []string
 	// nextStateID is the id allocated for the next
 	// StateOp.
 	nextStateID int
@@ -183,8 +194,12 @@ func Reset(o *Ops) {
 	for i := range o.refs {
 		o.refs[i] = nil
 	}
+	for i := range o.stringRefs {
+		o.stringRefs[i] = ""
+	}
 	o.data = o.data[:0]
 	o.refs = o.refs[:0]
+	o.stringRefs = o.stringRefs[:0]
 	o.nextStateID = 0
 	o.version++
 }
@@ -265,12 +280,26 @@ func Write1(o *Ops, n int, ref1 interface{}) []byte {
 	return o.data[len(o.data)-n:]
 }
 
+func Write1String(o *Ops, n int, ref1 string) []byte {
+	o.data = append(o.data, make([]byte, n)...)
+	o.stringRefs = append(o.stringRefs, ref1)
+	o.refs = append(o.refs, &o.stringRefs[len(o.stringRefs)-1])
+	return o.data[len(o.data)-n:]
+}
+
 func Write2(o *Ops, n int, ref1, ref2 interface{}) []byte {
 	o.data = append(o.data, make([]byte, n)...)
 	o.refs = append(o.refs, ref1, ref2)
 	return o.data[len(o.data)-n:]
 }
 
+func Write2String(o *Ops, n int, ref1 interface{}, ref2 string) []byte {
+	o.data = append(o.data, make([]byte, n)...)
+	o.stringRefs = append(o.stringRefs, ref2)
+	o.refs = append(o.refs, ref1, &o.stringRefs[len(o.stringRefs)-1])
+	return o.data[len(o.data)-n:]
+}
+
 func Write3(o *Ops, n int, ref1, ref2, ref3 interface{}) []byte {
 	o.data = append(o.data, make([]byte, n)...)
 	o.refs = append(o.refs, ref1, ref2, ref3)
diff --git a/io/clipboard/clipboard.go b/io/clipboard/clipboard.go
index ae4a4359..474ae9bb 100644
--- a/io/clipboard/clipboard.go
+++ b/io/clipboard/clipboard.go
@@ -30,7 +30,7 @@ func (h ReadOp) Add(o *op.Ops) {
 }
 
 func (h WriteOp) Add(o *op.Ops) {
-	data := ops.Write1(&o.Internal, ops.TypeClipboardWriteLen, &h.Text)
+	data := ops.Write1String(&o.Internal, ops.TypeClipboardWriteLen, h.Text)
 	data[0] = byte(ops.TypeClipboardWrite)
 }
 
diff --git a/io/key/key.go b/io/key/key.go
index 53cdf926..18d27bc8 100644
--- a/io/key/key.go
+++ b/io/key/key.go
@@ -323,8 +323,7 @@ func (h InputOp) Add(o *op.Ops) {
 	if h.Tag == nil {
 		panic("Tag must be non-nil")
 	}
-	filter := h.Keys
-	data := ops.Write2(&o.Internal, ops.TypeKeyInputLen, h.Tag, &filter)
+	data := ops.Write2String(&o.Internal, ops.TypeKeyInputLen, h.Tag, string(h.Keys))
 	data[0] = byte(ops.TypeKeyInput)
 	data[1] = byte(h.Hint)
 }
@@ -343,7 +342,7 @@ func (h FocusOp) Add(o *op.Ops) {
 }
 
 func (s SnippetOp) Add(o *op.Ops) {
-	data := ops.Write2(&o.Internal, ops.TypeSnippetLen, s.Tag, &s.Text)
+	data := ops.Write2String(&o.Internal, ops.TypeSnippetLen, s.Tag, s.Text)
 	data[0] = byte(ops.TypeSnippet)
 	bo := binary.LittleEndian
 	bo.PutUint32(data[1:], uint32(s.Range.Start))
diff --git a/io/router/router.go b/io/router/router.go
index c7fad915..0c691c7c 100644
--- a/io/router/router.go
+++ b/io/router/router.go
@@ -490,11 +490,11 @@ func (q *Router) collect() {
 			}
 			kc.softKeyboard(op.Show)
 		case ops.TypeKeyInput:
-			filter := encOp.Refs[1].(*key.Set)
+			filter := key.Set(*encOp.Refs[1].(*string))
 			op := key.InputOp{
 				Tag:  encOp.Refs[0].(event.Tag),
 				Hint: key.InputHint(encOp.Data[1]),
-				Keys: *filter,
+				Keys: filter,
 			}
 			a := pc.currentArea()
 			b := pc.currentAreaBounds()
@@ -532,10 +532,10 @@ func (q *Router) collect() {
 
 		// Semantic ops.
 		case ops.TypeSemanticLabel:
-			lbl := encOp.Refs[0].(string)
+			lbl := *encOp.Refs[0].(*string)
 			pc.semanticLabel(lbl)
 		case ops.TypeSemanticDesc:
-			desc := encOp.Refs[0].(string)
+			desc := *encOp.Refs[0].(*string)
 			pc.semanticDesc(desc)
 		case ops.TypeSemanticClass:
 			class := semantic.ClassOp(encOp.Data[1])
diff --git a/io/semantic/semantic.go b/io/semantic/semantic.go
index 86e2b20e..569446a2 100644
--- a/io/semantic/semantic.go
+++ b/io/semantic/semantic.go
@@ -40,12 +40,12 @@ type SelectedOp bool
 type DisabledOp bool
 
 func (l LabelOp) Add(o *op.Ops) {
-	data := ops.Write1(&o.Internal, ops.TypeSemanticLabelLen, string(l))
+	data := ops.Write1String(&o.Internal, ops.TypeSemanticLabelLen, string(l))
 	data[0] = byte(ops.TypeSemanticLabel)
 }
 
 func (d DescriptionOp) Add(o *op.Ops) {
-	data := ops.Write1(&o.Internal, ops.TypeSemanticDescLen, string(d))
+	data := ops.Write1String(&o.Internal, ops.TypeSemanticDescLen, string(d))
 	data[0] = byte(ops.TypeSemanticDesc)
 }