diff --git a/contrib/teamcity/build-configurations.yml b/contrib/teamcity/build-configurations.yml
--- a/contrib/teamcity/build-configurations.yml
+++ b/contrib/teamcity/build-configurations.yml
@@ -97,6 +97,8 @@
         echo "Test depends on ecash-lib-wasm. Building WebAssembly..."
         pushd "${TOPLEVEL}/modules/ecash-lib-wasm"
         ./build-wasm.sh
+        sha256sum target/wasm32-unknown-unknown/release-wasm/ecash_lib_wasm.wasm
+        echo "24397b6d661e3186c83677464f50ed0fa902236ee0d4585de9f8c2d00792ac32 target/wasm32-unknown-unknown/release-wasm/ecash_lib_wasm.wasm" | sha256sum -c
       fi
 
       if [ -z "${DEPENDS_CHRONIK_CLIENT+x}" ] ; then
diff --git a/modules/ecash-lib-wasm/.gitignore b/modules/ecash-lib-wasm/.gitignore
--- a/modules/ecash-lib-wasm/.gitignore
+++ b/modules/ecash-lib-wasm/.gitignore
@@ -1 +1,2 @@
 /target
+Cargo.lock
diff --git a/modules/ecash-lib/README.md b/modules/ecash-lib/README.md
--- a/modules/ecash-lib/README.md
+++ b/modules/ecash-lib/README.md
@@ -2,6 +2,22 @@
 
 Library for eCash transaction building.
 
+## Development
+
+`ecash-lib-wasm` must be built and in-place before `ecash-lib` can be built. To do this locally,
+
+```
+cd ../ecash-lib-wasm
+./dockerbuild.sh
+```
+
+In CI,
+
+```
+./build-wasm.sh
+echo "55bc25a70a1ef5e76720593295b0e68cebc54dd1c0ade5124f2c11fa1346b08f target/wasm32-unknown-unknown/release-wasm/ecash_lib_wasm.wasm" | sha256sum -c
+```
+
 ## Usage
 
 ```ts