diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 00000000..33b79214
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,14 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: "cargo"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: "cargo"
+    directory: "/invoice"
+    schedule:
+      interval: "weekly"
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 24874bf7..e2a308d9 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -1,10 +1,16 @@
-name: Build
+name: Build Check
 
 on:
   push:
-    branches: [ master ]
+    branches:
+      - master
+      - develop
+      - 'v[0-9]+.[0-9]+'
   pull_request:
-    branches: [ master ]
+    branches:
+      - master
+      - develop
+      - 'v[0-9]+.[0-9]+'
 
 env:
   CARGO_TERM_COLOR: always
@@ -13,13 +19,14 @@ jobs:
   default:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
+      # NOTE: Dont use nix here, everything should be based on the ubuntu-latest
       - name: Install rust stable
         uses: actions-rs/toolchain@v1
         with:
           toolchain: stable
           override: true
-      - name: Default build
+      - name: Latest Ubuntu build check
         uses: actions-rs/cargo@v1
         with:
           command: check
@@ -33,22 +40,13 @@ jobs:
           - fs
           - serde
     steps:
-      - uses: actions/checkout@v2
-      - name: Install rust stable
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          override: true
-      - name: Feature ${{ matrix.feature }}
-        uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: --no-default-features --features=${{ matrix.feature }}
-      - name: Defaults + ${{ matrix.feature }}
-        uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: --features=${{ matrix.feature }}
+      - uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v26
+      - name: Check feature ${{ matrix.feature }} only
+        run: nix develop .#stable -c cargo check --no-default-features --features=${{ matrix.feature }}
+      - name: Check feature ${{ matrix.feature }} with defaults
+        run: nix develop .#stable -c cargo check --features=${{ matrix.feature }}
   platforms:
     runs-on: ${{ matrix.os }}
     strategy:
@@ -56,13 +54,14 @@ jobs:
       matrix:
         os: [ ubuntu-20.04, ubuntu-22.04, macos-12, macos-13, windows-2019, windows-2022 ]
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
+      # NOTE: Dont use nix in platform checks everything should based on the host system
       - name: Install rust stable
         uses: actions-rs/toolchain@v1
         with:
           toolchain: stable
           override: true
-      - name: Build with all features
+      - name: Build check with all features
         uses: actions-rs/cargo@v1
         with:
           command: check
@@ -72,16 +71,11 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        toolchain: [ nightly, beta, stable, 1.75.0 ]
+        toolchain: [ nightly, beta, stable, msrv ]
     steps:
-      - uses: actions/checkout@v2
-      - name: Install rust ${{ matrix.toolchain }}
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: ${{ matrix.toolchain }}
-          override: true
-      - name: All features
-        uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: --workspace --all-targets --all-features
+      - name: checkout
+        uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v26
+      - name: Check Crates
+        run: nix develop ".#${{ matrix.toolchain }}" -c cargo check --workspace --all-targets --all-features
diff --git a/.github/workflows/codecov.yml b/.github/workflows/codecov.yml
index 20773195..4a23e91b 100644
--- a/.github/workflows/codecov.yml
+++ b/.github/workflows/codecov.yml
@@ -2,9 +2,15 @@ name: Codecov
 
 on:
   push:
-    branches: [ master ]
+    branches:
+      - master
+      - develop
+      - 'v[0-9]+.[0-9]+'
   pull_request:
-    branches: [ master ]
+    branches:
+      - master
+      - develop
+      - 'v[0-9]+.[0-9]+'
 
 env:
   CARGO_TERM_COLOR: always
@@ -14,38 +20,22 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: Set up toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
-          components: rustfmt, llvm-tools-preview
+      - name: Install Nix
+        uses: cachix/install-nix-action@v26
       - name: Build
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --release
-        env:
-          CARGO_INCREMENTAL: "0"
-          RUSTFLAGS: "-Cinstrument-coverage"
-          RUSTDOCFLAGS: "-Cinstrument-coverage"
+        run: nix develop .#codecov -c cargo build --release
       - name: Test
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --all-features --no-fail-fast
-        env:
-          CARGO_INCREMENTAL: "0"
-          RUSTFLAGS: "-Cinstrument-coverage"
-          RUSTDOCFLAGS: "-Cinstrument-coverage"
+        run: nix develop .#codecov -c cargo test --all-features --no-fail-fast --tests
       - name: Install grcov
-        run: if [[ ! -e ~/.cargo/bin/grcov ]]; then cargo install grcov; fi
+        run: nix develop .#codecov -c cargo install grcov
       - name: Generate coverage
-        run: grcov . --binary-path target/debug/deps/ -s . -t lcov --branch --ignore-not-existing --ignore '../**' --ignore '/*' -o coverage.lcov
+        run: nix develop .#codecov -c grcov . --binary-path target/debug/deps/ -s . -t lcov --branch --ignore-not-existing --ignore '../**' --ignore '/*' -o coverage.lcov
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v3
+        uses: codecov/codecov-action@v4
         with:
           files: ./coverage.lcov
           flags: rust
-          fail_ci_if_error: true
+          # TODO: set true when CODECOV_TOKEN is set
+          fail_ci_if_error: false
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 3f51bde0..7ca82979 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -2,9 +2,15 @@ name: Lints
 
 on:
   push:
-    branches: [ master ]
+    branches:
+      - master
+      - develop
+      - 'v[0-9]+.[0-9]+'
   pull_request:
-    branches: [ master ]
+    branches:
+      - master
+      - develop
+      - 'v[0-9]+.[0-9]+'
 
 env:
   CARGO_TERM_COLOR: always
@@ -13,45 +19,24 @@ jobs:
   fmt:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - name: Install rustc nightly
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          override: true
-          components: rustfmt
-      - uses: actions-rs/cargo@v1
-        name: Formatting
-        with:
-          command: fmt
-          args: --all -- --check
+      - uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v26
+      - name: Formatting
+        run: nix develop .#nightly -c cargo fmt --all -- --check
   clippy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - name: Install rustc stable
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          override: true
-          components: clippy
-      - uses: actions-rs/cargo@v1
-        name: Clippy
-        with:
-          command: clippy
-          args: --workspace --all-features --all-targets -- -D warnings
+      - uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v26
+      - name: Clippy
+        run: nix develop .#stable -c cargo clippy --workspace --all-features --all-targets -- -D warnings
   doc:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - name: Install rustc nightly
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          override: true
-          components: rust-docs
-      - uses: actions-rs/cargo@v1
-        name: Doc
-        with:
-          command: doc
-          args: --workspace --all-features
+      - uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v26
+      - name: Doc
+        run: nix develop .#nightly -c cargo doc --workspace --all-features
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f40b2cd0..1dae2740 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -2,9 +2,15 @@ name: Tests
 
 on:
   push:
-    branches: [ master ]
+    branches:
+      - master
+      - develop
+      - 'v[0-9]+.[0-9]+'
   pull_request:
-    branches: [ master ]
+    branches:
+      - master
+      - develop
+      - 'v[0-9]+.[0-9]+'
 
 env:
   CARGO_TERM_COLOR: always
@@ -13,29 +19,16 @@ jobs:
   testing:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - name: Install latest stable
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          override: true
+      - uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v26
       - name: Build & test
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --workspace --all-features --no-fail-fast
+        run: nix develop .#stable -c cargo test --workspace --all-features --no-fail-fast --tests
   wasm-testing:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - name: Install rust nightly
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          override: true
-      - uses: Swatinem/rust-cache@v2
-      - uses: jetli/wasm-pack-action@v0.3.0
-      - name: Add wasm32 target
-        run: rustup target add wasm32-unknown-unknown
+      - uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v26
       - name: Test in headless Chrome
-        run: wasm-pack test --headless --chrome
+        run: nix develop .#wasm -c wasm-pack test --headless --chrome
diff --git a/.gitignore b/.gitignore
index e8ab911e..2f2af66b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,3 +10,6 @@
 *.swp
 
 /dep_test
+result
+default_*.profraw
+coverage.lcov
diff --git a/README.md b/README.md
index cd72d957..7e26ed0b 100644
--- a/README.md
+++ b/README.md
@@ -56,7 +56,7 @@ by default.
 
 ### MSRV
 
-Minimum supported rust compiler version (MSRV): 1.66, rust 2021 edition.
+Minimum supported rust compiler version (MSRV) is shown in `rust-version` of `Cargo.toml`.
 
 ## Contributing
 
diff --git a/asset/armored_contract.default b/asset/armored_contract.default
new file mode 100644
index 00000000..106d24d0
--- /dev/null
+++ b/asset/armored_contract.default
@@ -0,0 +1,13 @@
+-----BEGIN RGB CONSIGNMENT-----
+Id: rgb:csg:poAMvm9j-NdapxqA-MJ@5dwP-d@IIt2A-T@5OiXE-Tl54Yew#guide-campus-arctic
+Version: 2
+Type: contract
+Contract: rgb:qm7P@06T-uuBQT56-ovwOLzx-9Gka7Nb-84Nwo8g-blLb8kw
+Schema: rgb:sch:CyqM42yAdM1moWyNZPQedAYt73BM$k9z$dKLUXY1voA#cello-global-deluxe
+Check-SHA256: 181748dae0c83cbb44f6ccfdaddf6faca0bc4122a9f35fef47bab9aea023e4a1
+
+0ssI2000000000000000000000000000000000000000000000000000000D0CRI`I$>^aZh38Qb#nj!
+0000000000000000000000d59ZDjxe00000000dDb8~4rVQz13d2MfXa{vGU00000000000000000000
+0000000000000
+
+-----END RGB CONSIGNMENT-----
diff --git a/asset/armored_kit.default b/asset/armored_kit.default
new file mode 100644
index 00000000..3cd1403e
--- /dev/null
+++ b/asset/armored_kit.default
@@ -0,0 +1,9 @@
+-----BEGIN RGB KIT-----
+Id: rgb:kit:e1jW6Rgc-2$JzXDg-XmR8XRJ-v@q$Dzf-yImkPjD-t8EjfvI
+Version: 2
+Type-System: sts:8Vb$sM1F-5MsQc20-HEixf55-gJR37FM-0zRKfpY-SwIp35w#design-farmer-camel
+Check-SHA256: 5563cc1568e244183804e0db3cec6ff9bf577f4a403924096177bf4a586160da
+
+0ssI2000000000
+
+-----END RGB KIT-----
diff --git a/asset/armored_transfer.default b/asset/armored_transfer.default
new file mode 100644
index 00000000..106d24d0
--- /dev/null
+++ b/asset/armored_transfer.default
@@ -0,0 +1,13 @@
+-----BEGIN RGB CONSIGNMENT-----
+Id: rgb:csg:poAMvm9j-NdapxqA-MJ@5dwP-d@IIt2A-T@5OiXE-Tl54Yew#guide-campus-arctic
+Version: 2
+Type: contract
+Contract: rgb:qm7P@06T-uuBQT56-ovwOLzx-9Gka7Nb-84Nwo8g-blLb8kw
+Schema: rgb:sch:CyqM42yAdM1moWyNZPQedAYt73BM$k9z$dKLUXY1voA#cello-global-deluxe
+Check-SHA256: 181748dae0c83cbb44f6ccfdaddf6faca0bc4122a9f35fef47bab9aea023e4a1
+
+0ssI2000000000000000000000000000000000000000000000000000000D0CRI`I$>^aZh38Qb#nj!
+0000000000000000000000d59ZDjxe00000000dDb8~4rVQz13d2MfXa{vGU00000000000000000000
+0000000000000
+
+-----END RGB CONSIGNMENT-----
diff --git a/asset/contract.default b/asset/contract.default
new file mode 100644
index 00000000..33e2bd71
Binary files /dev/null and b/asset/contract.default differ
diff --git a/asset/kit.default b/asset/kit.default
new file mode 100644
index 00000000..67d729f7
Binary files /dev/null and b/asset/kit.default differ
diff --git a/asset/transfer.default b/asset/transfer.default
new file mode 100644
index 00000000..2ae06b2d
Binary files /dev/null and b/asset/transfer.default differ
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 00000000..6894ac04
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,85 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1710146030,
+        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1712439257,
+        "narHash": "sha256-aSpiNepFOMk9932HOax0XwNxbA38GOUVOiXfUVPOrck=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "ff0dbd94265ac470dda06a657d5fe49de93b4599",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1712542394,
+        "narHash": "sha256-UZebDBECRSrJqw4K+LxZ6qFdYnScu6q1XCwqtsu1cas=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "ece8bdb3c3b58def25f204b9a1261dee55d7c9c0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 00000000..97a9cc3d
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,80 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+      inputs.flake-utils.follows = "flake-utils";
+    };
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, rust-overlay, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs {
+          inherit system overlays;
+        };
+
+        cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
+
+        nightlyWithWasm = pkgs.rust-bin.nightly.latest.default.override {
+          extensions = [ ];
+          targets = [ "wasm32-unknown-unknown" ];
+        };
+
+        stableWithLlvm = pkgs.rust-bin.nightly.latest.default.override {
+          extensions = [ "rustfmt" "llvm-tools-preview" ];
+          targets = [ ];
+        };
+      in
+      with pkgs;
+      {
+        devShells = rec {
+          default = msrv;
+
+          msrv = mkShell {
+            buildInputs = [
+              rust-bin.stable."${cargoToml.workspace.package."rust-version"}".default
+            ];
+          };
+
+          stable = mkShell {
+            buildInputs = [
+              rust-bin.stable.latest.default
+            ];
+          };
+
+          beta = mkShell {
+            buildInputs = [
+              rust-bin.beta.latest.default
+            ];
+          };
+
+          nightly = mkShell {
+            buildInputs = [
+              rust-bin.nightly.latest.default
+            ];
+          };
+
+          wasm = mkShell {
+            buildInputs = [
+              nightlyWithWasm
+              chromedriver
+              wasm-pack
+            ];
+          };
+
+          codecov = mkShell {
+            buildInputs = [
+              stableWithLlvm
+            ];
+            CARGO_INCREMENTAL = "0";
+            RUSTFLAGS = "-Cinstrument-coverage";
+            RUSTDOCFLAGS = "-Cinstrument-coverage";
+          };
+        };
+      }
+    );
+}
diff --git a/src/containers/consignment.rs b/src/containers/consignment.rs
index 0064ccff..e483fe33 100644
--- a/src/containers/consignment.rs
+++ b/src/containers/consignment.rs
@@ -137,7 +137,7 @@ impl<const TRANSFER: bool> Deref for ValidConsignment<TRANSFER> {
 /// with `endpoints` and process up to the genesis.
 #[derive(Clone, Debug, Display)]
 #[display(AsciiArmor::to_ascii_armored_string)]
-#[derive(StrictType, StrictDumb, StrictEncode, StrictDecode)]
+#[derive(StrictType, StrictDumb, StrictEncode, StrictDecode, PartialEq)]
 #[strict_type(lib = LIB_NAME_RGB_STD)]
 #[cfg_attr(
     feature = "serde",
@@ -377,7 +377,7 @@ impl<const TRANSFER: bool> StrictArmor for Consignment<TRANSFER> {
 
     fn armor_id(&self) -> Self::Id { self.commit_id() }
     fn armor_headers(&self) -> Vec<ArmorHeader> {
-        vec![
+        let mut headers = vec![
             ArmorHeader::new(ASCII_ARMOR_VERSION, format!("{:#}", self.version)),
             ArmorHeader::new(
                 ASCII_ARMOR_CONSIGNMENT_TYPE,
@@ -389,11 +389,175 @@ impl<const TRANSFER: bool> StrictArmor for Consignment<TRANSFER> {
             ),
             ArmorHeader::new(ASCII_ARMOR_CONTRACT, self.contract_id().to_string()),
             ArmorHeader::new(ASCII_ARMOR_SCHEMA, self.schema.schema_id().to_string()),
-            ArmorHeader::with(
+        ];
+        if !self.ifaces.is_empty() {
+            headers.push(ArmorHeader::with(
                 ASCII_ARMOR_IFACE,
                 self.ifaces.keys().map(|iface| iface.name.to_string()),
-            ),
-            ArmorHeader::with(ASCII_ARMOR_TERMINAL, self.terminals.keys().map(BundleId::to_string)),
-        ]
+            ));
+        }
+        if !self.terminals.is_empty() {
+            headers.push(ArmorHeader::with(
+                ASCII_ARMOR_TERMINAL,
+                self.terminals.keys().map(BundleId::to_string),
+            ));
+        }
+        headers
+    }
+}
+
+impl<const TRANSFER: bool> FromStr for Consignment<TRANSFER> {
+    type Err = armor::StrictArmorError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> { Self::from_ascii_armored_str(s) }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn contract_str_round_trip() {
+        let contract = Contract::from_str(include_str!("../../asset/armored_contract.default"))
+            .expect("contract from str should work");
+        assert_eq!(
+            contract.to_string(),
+            include_str!("../../asset/armored_contract.default"),
+            "contract string round trip fails"
+        );
+    }
+
+    #[test]
+    fn error_contract_strs() {
+        assert!(
+            Contract::from_str(
+                r#"-----BEGIN RGB CONSIGNMENT-----
+Id: rgb:csg:poAMvm9j-NdapxqA-MJ@5dwP-d@IIt2A-T@5OiXE-Tl54Yew#guide-campus-arctic
+Version: 2
+Type: contract
+Contract: rgb:qm7P@06T-uuBQT56-ovwOLzx-9Gka7Nb-84Nwo8g-blLb8kw
+Schema: rgb:sch:CyqM42yAdM1moWyNZPQedAYt73BM$k9z$dKLUXY1voA#cello-global-deluxe
+Check-SHA256: 181748dae0c83cbb44f6ccfdaddf6faca0bc4122a9f35fef47bab9aea023e4a1
+
+0ssI2000000000000000000000000000000000000000000000000000000D0CRI`I$>^aZh38Qb#nj!
+0000000000000000000000d59ZDjxe00000000dDb8~4rVQz13d2MfXa{vGU00000000000000000000
+0000000000000
+
+-----END RGB CONSIGNMENT-----"#
+            )
+            .is_ok()
+        );
+
+        // Wrong Id
+        assert!(
+            Contract::from_str(
+                r#"-----BEGIN RGB CONSIGNMENT-----
+Id: rgb:csg:aaaaaaaa-aaaaaaa-aaaaaaa-aaaaaaa-aaaaaaa-aaaaaaa#guide-campus-arctic
+Version: 2
+Type: contract
+Contract: rgb:qm7P@06T-uuBQT56-ovwOLzx-9Gka7Nb-84Nwo8g-blLb8kw
+Schema: rgb:sch:CyqM42yAdM1moWyNZPQedAYt73BM$k9z$dKLUXY1voA#cello-global-deluxe
+Check-SHA256: 181748dae0c83cbb44f6ccfdaddf6faca0bc4122a9f35fef47bab9aea023e4a1
+
+0ssI2000000000000000000000000000000000000000000000000000000D0CRI`I$>^aZh38Qb#nj!
+0000000000000000000000d59ZDjxe00000000dDb8~4rVQz13d2MfXa{vGU00000000000000000000
+0000000000000
+
+-----END RGB CONSIGNMENT-----"#
+            )
+            .is_err()
+        );
+
+        // Wrong checksum
+        assert!(
+            Contract::from_str(
+                r#"-----BEGIN RGB CONSIGNMENT-----
+Id: rgb:csg:poAMvm9j-NdapxqA-MJ@5dwP-d@IIt2A-T@5OiXE-Tl54Yew#guide-campus-arctic
+Version: 2
+Type: contract
+Contract: rgb:qm7P@06T-uuBQT56-ovwOLzx-9Gka7Nb-84Nwo8g-blLb8kw
+Schema: rgb:sch:CyqM42yAdM1moWyNZPQedAYt73BM$k9z$dKLUXY1voA#cello-global-deluxe
+Check-SHA256: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+
+0ssI2000000000000000000000000000000000000000000000000000000D0CRI`I$>^aZh38Qb#nj!
+0000000000000000000000d59ZDjxe00000000dDb8~4rVQz13d2MfXa{vGU00000000000000000000
+0000000000000
+
+-----END RGB CONSIGNMENT-----"#
+            )
+            .is_err()
+        );
+    }
+
+    #[test]
+    fn transfer_str_round_trip() {
+        let transfer = Transfer::from_str(include_str!("../../asset/armored_transfer.default"))
+            .expect("transfer from str should work");
+        assert_eq!(
+            transfer.to_string(),
+            include_str!("../../asset/armored_transfer.default"),
+            "transfer string round trip fails"
+        );
+    }
+
+    #[test]
+    fn error_transfer_strs() {
+        assert!(
+            Transfer::from_str(
+                r#"-----BEGIN RGB CONSIGNMENT-----
+Id: rgb:csg:poAMvm9j-NdapxqA-MJ@5dwP-d@IIt2A-T@5OiXE-Tl54Yew#guide-campus-arctic
+Version: 2
+Type: contract
+Contract: rgb:qm7P@06T-uuBQT56-ovwOLzx-9Gka7Nb-84Nwo8g-blLb8kw
+Schema: rgb:sch:CyqM42yAdM1moWyNZPQedAYt73BM$k9z$dKLUXY1voA#cello-global-deluxe
+Check-SHA256: 181748dae0c83cbb44f6ccfdaddf6faca0bc4122a9f35fef47bab9aea023e4a1
+
+0ssI2000000000000000000000000000000000000000000000000000000D0CRI`I$>^aZh38Qb#nj!
+0000000000000000000000d59ZDjxe00000000dDb8~4rVQz13d2MfXa{vGU00000000000000000000
+0000000000000
+
+-----END RGB CONSIGNMENT-----"#
+            )
+            .is_ok()
+        );
+
+        // Wrong Id
+        assert!(
+            Transfer::from_str(
+                r#"-----BEGIN RGB CONSIGNMENT-----
+Id: rgb:csg:aaaaaaaa-aaaaaaa-aaaaaaa-aaaaaaa-aaaaaaa-aaaaaaa#guide-campus-arctic
+Version: 2
+Type: contract
+Contract: rgb:qm7P@06T-uuBQT56-ovwOLzx-9Gka7Nb-84Nwo8g-blLb8kw
+Schema: rgb:sch:CyqM42yAdM1moWyNZPQedAYt73BM$k9z$dKLUXY1voA#cello-global-deluxe
+Check-SHA256: 181748dae0c83cbb44f6ccfdaddf6faca0bc4122a9f35fef47bab9aea023e4a1
+
+0ssI2000000000000000000000000000000000000000000000000000000D0CRI`I$>^aZh38Qb#nj!
+0000000000000000000000d59ZDjxe00000000dDb8~4rVQz13d2MfXa{vGU00000000000000000000
+0000000000000
+
+-----END RGB CONSIGNMENT-----"#
+            )
+            .is_err()
+        );
+
+        // Wrong checksum
+        assert!(
+            Transfer::from_str(
+                r#"-----BEGIN RGB CONSIGNMENT-----
+Id: rgb:csg:poAMvm9j-NdapxqA-MJ@5dwP-d@IIt2A-T@5OiXE-Tl54Yew#guide-campus-arctic
+Version: 2
+Type: contract
+Contract: rgb:qm7P@06T-uuBQT56-ovwOLzx-9Gka7Nb-84Nwo8g-blLb8kw
+Schema: rgb:sch:CyqM42yAdM1moWyNZPQedAYt73BM$k9z$dKLUXY1voA#cello-global-deluxe
+Check-SHA256: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+
+0ssI2000000000000000000000000000000000000000000000000000000D0CRI`I$>^aZh38Qb#nj!
+0000000000000000000000d59ZDjxe00000000dDb8~4rVQz13d2MfXa{vGU00000000000000000000
+0000000000000
+
+-----END RGB CONSIGNMENT-----"#
+            )
+            .is_err()
+        );
     }
 }
diff --git a/src/containers/file.rs b/src/containers/file.rs
index 479364b5..78d02ef3 100644
--- a/src/containers/file.rs
+++ b/src/containers/file.rs
@@ -193,3 +193,262 @@ impl Display for UniversalFile {
         }
     }
 }
+
+#[cfg(test)]
+mod test {
+    use std::fs::OpenOptions;
+    use std::str::FromStr;
+
+    use super::*;
+    static DEFAULT_KIT_PATH: &str = "asset/kit.default";
+    #[cfg(feature = "fs")]
+    static ARMORED_KIT_PATH: &str = "asset/armored_kit.default";
+
+    static DEFAULT_CONTRACT_PATH: &str = "asset/contract.default";
+    #[cfg(feature = "fs")]
+    static ARMORED_CONTRACT_PATH: &str = "asset/armored_contract.default";
+
+    static DEFAULT_TRANSFER_PATH: &str = "asset/transfer.default";
+    #[cfg(feature = "fs")]
+    static ARMORED_TRANSFER_PATH: &str = "asset/armored_transfer.default";
+
+    #[test]
+    fn kit_save_load_round_trip() {
+        let mut kit_file = OpenOptions::new()
+            .read(true)
+            .open(DEFAULT_KIT_PATH)
+            .unwrap();
+        let kit = Kit::load(kit_file).expect("fail to load kit.default");
+        let default_kit = Kit::default();
+        assert_eq!(kit, default_kit, "kit default is not same as before");
+
+        kit_file = OpenOptions::new()
+            .write(true)
+            .open(DEFAULT_KIT_PATH)
+            .unwrap();
+        default_kit.save(kit_file).expect("fail to export kit");
+
+        kit_file = OpenOptions::new()
+            .read(true)
+            .open(DEFAULT_KIT_PATH)
+            .unwrap();
+        let kit = Kit::load(kit_file).expect("fail to load kit.default");
+        assert_eq!(kit, default_kit, "kit roudtrip does not work");
+    }
+
+    #[cfg(feature = "fs")]
+    #[test]
+    fn armored_kit_save_load_round_trip() {
+        let kit_file = OpenOptions::new()
+            .read(true)
+            .open(DEFAULT_KIT_PATH)
+            .unwrap();
+        let kit = Kit::load(kit_file).expect("fail to load kit.default");
+        let unarmored_kit =
+            Kit::load_armored(ARMORED_KIT_PATH).expect("fail to export armored kit");
+        assert_eq!(kit, unarmored_kit, "kit unarmored is not the same");
+
+        let default_kit = Kit::default();
+        default_kit
+            .save_armored(ARMORED_KIT_PATH)
+            .expect("fail to save armored kit");
+        let kit = Kit::load_armored(ARMORED_KIT_PATH).expect("fail to export armored kit");
+        assert_eq!(kit, default_kit, "armored kit roudtrip does not work");
+    }
+
+    // A contract with almost default fields
+    fn almost_default_contract() -> Contract {
+        Contract {
+            version: Default::default(),
+            transfer: Default::default(),
+            terminals: Default::default(),
+            genesis: rgb::Genesis {
+                ffv: Default::default(),
+                schema_id: rgb::SchemaId::from_str(
+                    "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA#distant-history-exotic",
+                )
+                .unwrap(),
+                flags: Default::default(),
+                timestamp: Default::default(),
+                issuer: Default::default(),
+                testnet: Default::default(),
+                alt_layers1: Default::default(),
+                asset_tags: Default::default(),
+                metadata: Default::default(),
+                globals: Default::default(),
+                assignments: Default::default(),
+                valencies: Default::default(),
+                validator: Default::default(),
+            },
+            extensions: Default::default(),
+            bundles: Default::default(),
+            schema: rgb::Schema {
+                ffv: Default::default(),
+                flags: Default::default(),
+                name: strict_encoding::TypeName::from_str("Name").unwrap(),
+                timestamp: Default::default(),
+                developer: Default::default(),
+                meta_types: Default::default(),
+                global_types: Default::default(),
+                owned_types: Default::default(),
+                valency_types: Default::default(),
+                genesis: Default::default(),
+                extensions: Default::default(),
+                transitions: Default::default(),
+                reserved: Default::default(),
+            },
+            ifaces: Default::default(),
+            supplements: Default::default(),
+            types: Default::default(),
+            scripts: Default::default(),
+            attachments: Default::default(),
+            signatures: Default::default(),
+        }
+    }
+
+    #[test]
+    fn contract_save_load_round_trip() {
+        let mut contract_file = OpenOptions::new()
+            .read(true)
+            .open(DEFAULT_CONTRACT_PATH)
+            .unwrap();
+        let contract = Contract::load(contract_file).expect("fail to load contract.default");
+
+        let default_contract = almost_default_contract();
+        assert_eq!(&contract, &default_contract, "contract default is not same as before");
+
+        contract_file = OpenOptions::new()
+            .write(true)
+            .open(DEFAULT_CONTRACT_PATH)
+            .unwrap();
+        default_contract
+            .save(contract_file)
+            .expect("fail to export contract");
+
+        contract_file = OpenOptions::new()
+            .read(true)
+            .open(DEFAULT_CONTRACT_PATH)
+            .unwrap();
+        let contract = Contract::load(contract_file).expect("fail to load contract.default");
+        assert_eq!(&contract, &default_contract, "contract roudtrip does not work");
+    }
+
+    #[cfg(feature = "fs")]
+    #[test]
+    fn armored_contract_save_load_round_trip() {
+        let contract_file = OpenOptions::new()
+            .read(true)
+            .open(DEFAULT_CONTRACT_PATH)
+            .unwrap();
+        let contract = Contract::load(contract_file).expect("fail to load contract.default");
+        let unarmored_contract =
+            Contract::load_armored(ARMORED_CONTRACT_PATH).expect("fail to export armored contract");
+        assert_eq!(contract, unarmored_contract, "contract unarmored is not the same");
+
+        let default_contract = almost_default_contract();
+        default_contract
+            .save_armored(ARMORED_CONTRACT_PATH)
+            .expect("fail to save armored contract");
+        let contract =
+            Contract::load_armored(ARMORED_CONTRACT_PATH).expect("fail to export armored contract");
+        assert_eq!(contract, default_contract, "armored contract roudtrip does not work");
+    }
+
+    // A transfer with almost default fields
+    fn almost_default_transfer() -> Transfer {
+        Transfer {
+            version: Default::default(),
+            transfer: Default::default(),
+            terminals: Default::default(),
+            genesis: rgb::Genesis {
+                ffv: Default::default(),
+                schema_id: rgb::SchemaId::from_str(
+                    "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA#distant-history-exotic",
+                )
+                .unwrap(),
+                flags: Default::default(),
+                timestamp: Default::default(),
+                issuer: Default::default(),
+                testnet: Default::default(),
+                alt_layers1: Default::default(),
+                asset_tags: Default::default(),
+                metadata: Default::default(),
+                globals: Default::default(),
+                assignments: Default::default(),
+                valencies: Default::default(),
+                validator: Default::default(),
+            },
+            extensions: Default::default(),
+            bundles: Default::default(),
+            schema: rgb::Schema {
+                ffv: Default::default(),
+                flags: Default::default(),
+                name: strict_encoding::TypeName::from_str("Name").unwrap(),
+                timestamp: Default::default(),
+                developer: Default::default(),
+                meta_types: Default::default(),
+                global_types: Default::default(),
+                owned_types: Default::default(),
+                valency_types: Default::default(),
+                genesis: Default::default(),
+                extensions: Default::default(),
+                transitions: Default::default(),
+                reserved: Default::default(),
+            },
+            ifaces: Default::default(),
+            supplements: Default::default(),
+            types: Default::default(),
+            scripts: Default::default(),
+            attachments: Default::default(),
+            signatures: Default::default(),
+        }
+    }
+
+    #[test]
+    fn transfer_save_load_round_trip() {
+        let mut transfer_file = OpenOptions::new()
+            .read(true)
+            .open(DEFAULT_TRANSFER_PATH)
+            .unwrap();
+        let transfer = Transfer::load(transfer_file).expect("fail to load transfer.default");
+
+        let default_transfer = almost_default_transfer();
+        assert_eq!(&transfer, &default_transfer, "transfer default is not same as before");
+
+        transfer_file = OpenOptions::new()
+            .write(true)
+            .open(DEFAULT_TRANSFER_PATH)
+            .unwrap();
+        default_transfer
+            .save(transfer_file)
+            .expect("fail to export transfer");
+
+        transfer_file = OpenOptions::new()
+            .read(true)
+            .open(DEFAULT_TRANSFER_PATH)
+            .unwrap();
+        let transfer = Transfer::load(transfer_file).expect("fail to load transfer.default");
+        assert_eq!(&transfer, &default_transfer, "transfer roudtrip does not work");
+    }
+
+    #[cfg(feature = "fs")]
+    #[test]
+    fn armored_transfer_save_load_round_trip() {
+        let transfer_file = OpenOptions::new()
+            .read(true)
+            .open(DEFAULT_TRANSFER_PATH)
+            .unwrap();
+        let transfer = Transfer::load(transfer_file).expect("fail to load transfer.default");
+        let unarmored_transfer =
+            Transfer::load_armored(ARMORED_TRANSFER_PATH).expect("fail to export armored transfer");
+        assert_eq!(transfer, unarmored_transfer, "transfer unarmored is not the same");
+
+        let default_transfer = almost_default_transfer();
+        default_transfer
+            .save_armored(ARMORED_TRANSFER_PATH)
+            .expect("fail to save armored transfer");
+        let transfer =
+            Transfer::load_armored(ARMORED_TRANSFER_PATH).expect("fail to export armored transfer");
+        assert_eq!(transfer, default_transfer, "armored transfer roudtrip does not work");
+    }
+}
diff --git a/src/containers/kit.rs b/src/containers/kit.rs
index 6457123c..ffac4378 100644
--- a/src/containers/kit.rs
+++ b/src/containers/kit.rs
@@ -110,7 +110,7 @@ impl Deref for ValidKit {
     fn deref(&self) -> &Self::Target { &self.kit }
 }
 
-#[derive(Clone, Default, Debug, Display)]
+#[derive(Clone, Default, Debug, Display, PartialEq)]
 #[display(AsciiArmor::to_ascii_armored_string)]
 #[derive(StrictType, StrictEncode, StrictDecode)]
 #[strict_type(lib = LIB_NAME_RGB_STD)]
@@ -263,3 +263,80 @@ impl StrictArmor for Kit {
         headers
     }
 }
+
+impl FromStr for Kit {
+    type Err = armor::StrictArmorError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> { Self::from_ascii_armored_str(s) }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    #[test]
+    fn kit_str_round_trip() {
+        let kit = Kit::from_str(include_str!("../../asset/armored_kit.default"))
+            .expect("kit from str should work");
+
+        assert_eq!(
+            kit.to_string(),
+            include_str!("../../asset/armored_kit.default"),
+            "kit string round trip fails"
+        );
+
+        assert_eq!(
+            kit.validate().unwrap().to_string(),
+            include_str!("../../asset/armored_kit.default"),
+            "validated kit string round trip fails"
+        );
+    }
+
+    #[test]
+    fn error_kit_strs() {
+        assert!(
+            Kit::from_str(
+                r#"-----BEGIN RGB KIT-----
+Id: rgb:kit:e1jW6Rgc-2$JzXDg-XmR8XRJ-v@q$Dzf-yImkPjD-t8EjfvI
+Version: 2
+Type-System: sts:8Vb$sM1F-5MsQc20-HEixf55-gJR37FM-0zRKfpY-SwIp35w#design-farmer-camel
+Check-SHA256: 5563cc1568e244183804e0db3cec6ff9bf577f4a403924096177bf4a586160da
+
+0ssI2000000000
+
+-----END RGB KIT-----"#
+            )
+            .is_ok()
+        );
+
+        // Wrong Id
+        assert!(
+            Kit::from_str(
+                r#"-----BEGIN RGB KIT-----
+Id: rgb:kit:11111111-2222222-XmR8XRJ-v@q$Dzf-yImkPjD-t8EjfvI
+Version: 2
+Type-System: sts:8Vb$sM1F-5MsQc20-HEixf55-gJR37FM-0zRKfpY-SwIp35w#design-farmer-camel
+Check-SHA256: 5563cc1568e244183804e0db3cec6ff9bf577f4a403924096177bf4a586160da
+
+0ssI2000000000
+
+-----END RGB KIT-----"#
+            )
+            .is_err()
+        );
+
+        // wrong checksum
+        assert!(
+            Kit::from_str(
+                r#"-----BEGIN RGB KIT-----
+Id: rgb:kit:e1jW6Rgc-2$JzXDg-XmR8XRJ-v@q$Dzf-yImkPjD-t8EjfvI
+Version: 2
+Type-System: sts:8Vb$sM1F-5MsQc20-HEixf55-gJR37FM-0zRKfpY-SwIp35w#design-farmer-camel
+Check-SHA256: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+
+0ssI2000000000
+
+-----END RGB KIT-----"#
+            )
+            .is_err()
+        );
+    }
+}