diff --git a/seqproto.go b/seqproto.go
new file mode 100644
index 0000000..fdc4632
--- /dev/null
+++ b/seqproto.go
@@ -0,0 +1,111 @@
+package gigaparsec
+
+func Seq3[In, Out, T1, T2, T3 any](
+	p1 Parser[In, T1],
+	p2 Parser[In, T2],
+	p3 Parser[In, T3],
+	f func(T1, T2, T3) Out,
+) Parser[In, Out] {
+	return func(s State[In]) (Result[In, Out], error) {
+		var anyConsumed bool
+		var failed bool
+		var msg Message
+		var next = s
+
+		r1, err := p1(next)
+		if err != nil {
+			return Result[In, Out]{}, err
+		}
+		anyConsumed = anyConsumed || r1.Consumed()
+		failed, _, msg = r1.Failed()
+		if failed {
+			return Fail[In, Out](anyConsumed, msg), nil
+		}
+		_, _, val1, next, _ := r1.Succeeded()
+
+		r2, err := p2(next)
+		if err != nil {
+			return Result[In, Out]{}, err
+		}
+		anyConsumed = anyConsumed || r2.Consumed()
+		failed, _, msg = r2.Failed()
+		if failed {
+			return Fail[In, Out](anyConsumed, msg), nil
+		}
+		_, _, val2, next, _ := r2.Succeeded()
+
+		r3, err := p3(next)
+		if err != nil {
+			return Result[In, Out]{}, err
+		}
+		anyConsumed = anyConsumed || r3.Consumed()
+		failed, _, msg = r3.Failed()
+		if failed {
+			return Fail[In, Out](anyConsumed, msg), nil
+		}
+		_, _, val3, next, _ := r3.Succeeded()
+
+		val := f(val1, val2, val3)
+		return Succeed(anyConsumed, val, next, MessageOK(s.Pos())), nil
+	}
+}
+
+func Bind3[In, Out, T1, T2, T3 any](
+	p Parser[In, T1],
+	f1 func(T1) Parser[In, T2],
+	f2 func(T2) Parser[In, T3],
+	f3 func(T3) Parser[In, Out],
+) Parser[In, Out] {
+	return func(s State[In]) (Result[In, Out], error) {
+		var anyConsumed bool
+		var failed bool
+		var msg Message
+		var next = s
+
+		r1, err := p(next)
+		if err != nil {
+			return Result[In, Out]{}, err
+		}
+		anyConsumed = anyConsumed || r1.Consumed()
+		failed, _, msg = r1.Failed()
+		if failed {
+			return Fail[In, Out](anyConsumed, msg), nil
+		}
+		_, _, val1, next, _ := r1.Succeeded()
+
+		r2, err := f1(val1)(next)
+		if err != nil {
+			return Result[In, Out]{}, err
+		}
+		anyConsumed = anyConsumed || r2.Consumed()
+		failed, _, msg = r2.Failed()
+		if failed {
+			return Fail[In, Out](anyConsumed, msg), nil
+		}
+		_, _, val2, next, _ := r2.Succeeded()
+
+		r3, err := f2(val2)(next)
+		if err != nil {
+			return Result[In, Out]{}, err
+		}
+		anyConsumed = anyConsumed || r3.Consumed()
+		failed, _, msg = r3.Failed()
+		if failed {
+			return Fail[In, Out](anyConsumed, msg), nil
+		}
+		_, _, val3, next, _ := r3.Succeeded()
+
+		r4, err := f3(val3)(next)
+		if err != nil {
+			return Result[In, Out]{}, err
+		}
+		anyConsumed = anyConsumed || r4.Consumed()
+		failed, _, msg = r4.Failed()
+		if failed {
+			return Fail[In, Out](anyConsumed, msg), nil
+		}
+		_, _, val4, next, _ := r4.Succeeded()
+
+		return Succeed(anyConsumed, val4, next, MessageOK(s.Pos())), nil
+	}
+}