diff --git a/coinlib/lib/src/crypto/hd_key.dart b/coinlib/lib/src/crypto/hd_key.dart
index 9bc2fad..b661d75 100644
--- a/coinlib/lib/src/crypto/hd_key.dart
+++ b/coinlib/lib/src/crypto/hd_key.dart
@@ -12,9 +12,9 @@ class InvalidHDKeyVersion implements Exception {}
 
 abstract class HDKey {
 
-  static int maxIndex = 0xffffffff;
-  static int hardenBit = 0x80000000;
-  static int encodedLength = 78;
+  static const maxIndex = 0xffffffff;
+  static const hardenBit = 0x80000000;
+  static const encodedLength = 78;
 
   final Uint8List _chaincode;
   final int depth;
diff --git a/coinlib/lib/src/encode/bech32.dart b/coinlib/lib/src/encode/bech32.dart
index 2f12f1c..a525277 100644
--- a/coinlib/lib/src/encode/bech32.dart
+++ b/coinlib/lib/src/encode/bech32.dart
@@ -81,10 +81,10 @@ enum Bech32Type { bech32, bech32m }
 /// words may need to be further converted into the required data.
 class Bech32 {
 
-  static int maxLength = 90;
-  static int checksumLength = 6;
-  static int bech32CheckConst = 1;
-  static int bech32mCheckConst = 0x2bc830a3;
+  static const maxLength = 90;
+  static const checksumLength = 6;
+  static const bech32CheckConst = 1;
+  static const bech32mCheckConst = 0x2bc830a3;
 
   final String hrp;
   final List<int> words;
diff --git a/coinlib/lib/src/scripts/operations.dart b/coinlib/lib/src/scripts/operations.dart
index e557d51..670d3e3 100644
--- a/coinlib/lib/src/scripts/operations.dart
+++ b/coinlib/lib/src/scripts/operations.dart
@@ -12,13 +12,12 @@ class PushDataNotMinimal implements Exception {}
 /// Represents a single operation or script pushdata
 abstract class ScriptOp {
 
-  static int op1Negate = scriptOpNameToCode["1NEGATE"]!;
-  static int op1 = scriptOpNameToCode["1"]!;
-  static int op16 = scriptOpNameToCode["16"]!;
-  static int pushData1 = scriptOpNameToCode["PUSHDATA1"]!;
-  static int pushData2 = pushData1+1;
-  static int pushData4 = pushData2+1;
-
+  static final op1Negate = scriptOpNameToCode["1NEGATE"]!;
+  static final op1 = scriptOpNameToCode["1"]!;
+  static final op16 = scriptOpNameToCode["16"]!;
+  static final pushData1 = scriptOpNameToCode["PUSHDATA1"]!;
+  static final pushData2 = pushData1+1;
+  static final pushData4 = pushData2+1;
   static final pushdataMatcherRegExp = RegExp(r"^<(\d+)-bytes>$");
 
   /// The compiled bytes for this operation
diff --git a/coinlib/lib/src/scripts/programs/multisig.dart b/coinlib/lib/src/scripts/programs/multisig.dart
index f2abb85..b1e0d62 100644
--- a/coinlib/lib/src/scripts/programs/multisig.dart
+++ b/coinlib/lib/src/scripts/programs/multisig.dart
@@ -6,8 +6,8 @@ import 'package:coinlib/src/scripts/script.dart';
 
 class MultisigProgram implements Program {
 
-  static int maxPubkeys = 20;
-  static ScriptOp checkmultisig = ScriptOpCode.fromName("CHECKMULTISIG");
+  static const maxPubkeys = 20;
+  static final checkmultisig = ScriptOpCode.fromName("CHECKMULTISIG");
 
   @override
   final Script script;
diff --git a/coinlib/lib/src/scripts/programs/p2pkh.dart b/coinlib/lib/src/scripts/programs/p2pkh.dart
index 7b71e6b..320ee6f 100644
--- a/coinlib/lib/src/scripts/programs/p2pkh.dart
+++ b/coinlib/lib/src/scripts/programs/p2pkh.dart
@@ -10,7 +10,7 @@ import 'package:coinlib/src/scripts/script.dart';
 /// satisfy this script with a signature.
 class P2PKH implements Program {
 
-  static Script template = Script.fromAsm(
+  static final template = Script.fromAsm(
     "OP_DUP OP_HASH160 <20-bytes> OP_EQUALVERIFY OP_CHECKSIG",
   );
 
diff --git a/coinlib/lib/src/scripts/programs/p2sh.dart b/coinlib/lib/src/scripts/programs/p2sh.dart
index 68ca998..90a713b 100644
--- a/coinlib/lib/src/scripts/programs/p2sh.dart
+++ b/coinlib/lib/src/scripts/programs/p2sh.dart
@@ -8,7 +8,7 @@ import 'package:coinlib/src/scripts/script.dart';
 /// Pay-to-Script-Hash program taking a 20-byte script hash for a redeem script.
 class P2SH implements Program {
 
-  static Script template = Script.fromAsm("OP_HASH160 <20-bytes> OP_EQUAL");
+  static final template = Script.fromAsm("OP_HASH160 <20-bytes> OP_EQUAL");
 
   @override
   final Script script;
diff --git a/coinlib/lib/src/tx/output.dart b/coinlib/lib/src/tx/output.dart
index f86a587..20eec2f 100644
--- a/coinlib/lib/src/tx/output.dart
+++ b/coinlib/lib/src/tx/output.dart
@@ -10,7 +10,7 @@ import 'package:coinlib/src/scripts/script.dart';
 class Output with Writable {
 
   /// Max 64-bit integer
-  static BigInt maxValue = (BigInt.from(1) << 64) - BigInt.one;
+  static final maxValue = (BigInt.from(1) << 64) - BigInt.one;
 
   final BigInt value;
   final Uint8List _scriptPubKey;
diff --git a/coinlib/lib/src/tx/sighash_type.dart b/coinlib/lib/src/tx/sighash_type.dart
index 1572960..05863eb 100644
--- a/coinlib/lib/src/tx/sighash_type.dart
+++ b/coinlib/lib/src/tx/sighash_type.dart
@@ -5,14 +5,14 @@
 class SigHashType {
 
   /// Value to sign all outputs
-  static const int allValue = 1;
+  static const allValue = 1;
   /// Value to sign no outputs
-  static const int noneValue = 2;
+  static const noneValue = 2;
   /// Value to sign the output at the same index as the input
-  static const int singleValue = 3;
+  static const singleValue = 3;
   /// Flag that can be combined with other hash type values to only sign the
   /// input containing the signature
-  static const int anyOneCanPayFlag = 0x80;
+  static const anyOneCanPayFlag = 0x80;
 
   /// The single byte representation of the sighash type. Use [all], [none],
   /// [single] and [anyonecanpay] to extract details of the type.
diff --git a/coinlib/lib/src/tx/transaction.dart b/coinlib/lib/src/tx/transaction.dart
index 7048603..44ca4a6 100644
--- a/coinlib/lib/src/tx/transaction.dart
+++ b/coinlib/lib/src/tx/transaction.dart
@@ -31,19 +31,19 @@ class CannotSignInput implements Exception {
 /// with witness data.
 class Transaction with Writable {
 
-  static Uint8List hashZero = Uint8List(32);
-  static Uint8List hashOne = Uint8List(32)..last = 1;
+  static final hashZero = Uint8List(32);
+  static final hashOne = Uint8List(32)..last = 1;
 
-  static const int currentVersion = 3;
-  static const int maxSize = 1000000;
+  static const currentVersion = 3;
+  static const maxSize = 1000000;
 
-  static const int minInputSize = 41;
-  static const int minOutputSize = 9;
-  static const int minOtherSize = 10;
+  static const minInputSize = 41;
+  static const minOutputSize = 9;
+  static const minOtherSize = 10;
 
-  static const int maxInputs
+  static const maxInputs
     = (maxSize - minOtherSize - minOutputSize) ~/ minInputSize;
-  static const int maxOutputs
+  static const maxOutputs
     = (maxSize - minOtherSize - minInputSize) ~/ minOutputSize;
 
   final int version;