diff --git a/README.md b/README.md
index 9388a90..6bc65e8 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ For most other editors, you can use the schemas by adding the `$schema` property
 }
 ```
 
-You can also use these schemas programatially. For example, Salesforce CLI uses these schema to do certain validation.
+You can also use these schemas programatically. For example, Salesforce CLI uses these schema to do certain validation.
 
 ```javascript
 const schemas = require('@salesforce/schemas');
@@ -33,6 +33,14 @@ const projectJsonSchema = require('@salesforce/schema/sfdx-project-schema.json']
 
 Run the `features-update` and `settings-update` scripts on every major release and open a PR with the new changes against the `main` branch to keep the schema files up to date
 
+## Generating Schema from TS files
+
+the /src folder contains the TS type used to generate the [`replacements`](https://developer.salesforce.com/docs/atlas.en-us.sfdx_dev.meta/sfdx_dev/sfdx_dev_ws_string_replace.htm?q=replacements) project property.
+
+You can define (or import and re-export) TS types and then use [this extension](https://marketplace.visualstudio.com/items?itemName=marcoq.vscode-typescript-to-json-schema). It adds a "Generate JSON Schema from type" action to your palette.
+
+The results go into `/compiled`, which can be used to copy-paste into the project.
+
 ## Bugs and Feedback
 
 To report issues or feedback with the schemas, open a bug on [GitHub](https://github.com/forcedotcom/schemas/issues).
diff --git a/compiled/replacements.json b/compiled/replacements.json
new file mode 100644
index 0000000..c90f04f
--- /dev/null
+++ b/compiled/replacements.json
@@ -0,0 +1,266 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$ref": "#/definitions/Replacements",
+  "definitions": {
+    "Replacements": {
+      "anyOf": [
+        {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "replaceWithFile": {
+              "type": "string"
+            },
+            "stringToReplace": {
+              "type": "string"
+            },
+            "filename": {
+              "type": "string"
+            },
+            "replaceWhenEnv": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "env": {
+                    "type": "string"
+                  },
+                  "value": {
+                    "type": "string"
+                  }
+                },
+                "required": ["env", "value"],
+                "additionalProperties": false
+              }
+            }
+          },
+          "required": ["filename", "replaceWithFile", "stringToReplace"]
+        },
+        {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "replaceWithEnv": {
+              "type": "string"
+            },
+            "stringToReplace": {
+              "type": "string"
+            },
+            "filename": {
+              "type": "string"
+            },
+            "replaceWhenEnv": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "env": {
+                    "type": "string"
+                  },
+                  "value": {
+                    "type": "string"
+                  }
+                },
+                "required": ["env", "value"],
+                "additionalProperties": false
+              }
+            }
+          },
+          "required": ["filename", "replaceWithEnv", "stringToReplace"]
+        },
+        {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "replaceWithFile": {
+              "type": "string"
+            },
+            "regexToReplace": {
+              "type": "string"
+            },
+            "filename": {
+              "type": "string"
+            },
+            "replaceWhenEnv": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "env": {
+                    "type": "string"
+                  },
+                  "value": {
+                    "type": "string"
+                  }
+                },
+                "required": ["env", "value"],
+                "additionalProperties": false
+              }
+            }
+          },
+          "required": ["filename", "regexToReplace", "replaceWithFile"]
+        },
+        {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "replaceWithEnv": {
+              "type": "string"
+            },
+            "regexToReplace": {
+              "type": "string"
+            },
+            "filename": {
+              "type": "string"
+            },
+            "replaceWhenEnv": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "env": {
+                    "type": "string"
+                  },
+                  "value": {
+                    "type": "string"
+                  }
+                },
+                "required": ["env", "value"],
+                "additionalProperties": false
+              }
+            }
+          },
+          "required": ["filename", "regexToReplace", "replaceWithEnv"]
+        },
+        {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "replaceWithFile": {
+              "type": "string"
+            },
+            "stringToReplace": {
+              "type": "string"
+            },
+            "glob": {
+              "type": "string"
+            },
+            "replaceWhenEnv": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "env": {
+                    "type": "string"
+                  },
+                  "value": {
+                    "type": "string"
+                  }
+                },
+                "required": ["env", "value"],
+                "additionalProperties": false
+              }
+            }
+          },
+          "required": ["glob", "replaceWithFile", "stringToReplace"]
+        },
+        {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "replaceWithEnv": {
+              "type": "string"
+            },
+            "stringToReplace": {
+              "type": "string"
+            },
+            "glob": {
+              "type": "string"
+            },
+            "replaceWhenEnv": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "env": {
+                    "type": "string"
+                  },
+                  "value": {
+                    "type": "string"
+                  }
+                },
+                "required": ["env", "value"],
+                "additionalProperties": false
+              }
+            }
+          },
+          "required": ["glob", "replaceWithEnv", "stringToReplace"]
+        },
+        {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "replaceWithFile": {
+              "type": "string"
+            },
+            "regexToReplace": {
+              "type": "string"
+            },
+            "glob": {
+              "type": "string"
+            },
+            "replaceWhenEnv": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "env": {
+                    "type": "string"
+                  },
+                  "value": {
+                    "type": "string"
+                  }
+                },
+                "required": ["env", "value"],
+                "additionalProperties": false
+              }
+            }
+          },
+          "required": ["glob", "regexToReplace", "replaceWithFile"]
+        },
+        {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "replaceWithEnv": {
+              "type": "string"
+            },
+            "regexToReplace": {
+              "type": "string"
+            },
+            "glob": {
+              "type": "string"
+            },
+            "replaceWhenEnv": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "env": {
+                    "type": "string"
+                  },
+                  "value": {
+                    "type": "string"
+                  }
+                },
+                "required": ["env", "value"],
+                "additionalProperties": false
+              }
+            }
+          },
+          "required": ["glob", "regexToReplace", "replaceWithEnv"]
+        }
+      ]
+    }
+  }
+}
diff --git a/examples/sfdx-project/replacements.json b/examples/sfdx-project/replacements.json
index 99a45d2..cb49f67 100644
--- a/examples/sfdx-project/replacements.json
+++ b/examples/sfdx-project/replacements.json
@@ -12,6 +12,11 @@
       "stringToReplace": "replaceMe",
       "replaceWithEnv": "THE_REPLACEMENT"
     },
+    {
+      "filename": "force-app/main/default/classes/myClass.cls",
+      "stringToReplace": "replaceMe",
+      "replaceWithFile": "~/substitutions.txt"
+    },
     {
       "glob": "**/*.cls",
       "regexToReplace": "\\d",
@@ -29,4 +34,4 @@
       ]
     }
   ]
-}
+}
\ No newline at end of file
diff --git a/package.json b/package.json
index cb6777f..4806d4a 100644
--- a/package.json
+++ b/package.json
@@ -30,9 +30,10 @@
   "devDependencies": {
     "@commitlint/cli": "^7",
     "@commitlint/config-conventional": "^7",
+    "@salesforce/dev-config": "^3.1.0",
+    "ajv": "^8.11.0",
     "commitizen": "^3.0.5",
     "cz-conventional-changelog": "^2.1.0",
-    "ajv": "^8.11.0",
     "husky": "^3.0.2",
     "jest": "^24.8.0",
     "prettier": "^1.18.2",
@@ -52,4 +53,4 @@
       "path": "./node_modules/cz-conventional-changelog"
     }
   }
-}
\ No newline at end of file
+}
diff --git a/sfdx-project.schema.json b/sfdx-project.schema.json
index dcd45a4..562a7cb 100644
--- a/sfdx-project.schema.json
+++ b/sfdx-project.schema.json
@@ -206,6 +206,15 @@
             "type": "object",
             "additionalProperties": false,
             "properties": {
+              "replaceWithFile": {
+                "type": "string"
+              },
+              "stringToReplace": {
+                "type": "string"
+              },
+              "filename": {
+                "type": "string"
+              },
               "replaceWhenEnv": {
                 "type": "array",
                 "items": {
@@ -215,30 +224,36 @@
                       "type": "string"
                     },
                     "value": {
-                      "type": ["string", "number", "boolean"]
+                      "type": "string"
                     }
                   },
-                  "required": ["env", "value"],
+                  "required": [
+                    "env",
+                    "value"
+                  ],
                   "additionalProperties": false
-                },
-                "maxItems": 1
-              },
-              "stringToReplace": {
-                "$ref": "#/definitions/replacements.stringToReplace"
-              },
-              "replaceWithEnv": {
-                "$ref": "#/definitions/replacements.replaceWithEnv"
-              },
-              "filename": {
-                "$ref": "#/definitions/replacements.filename"
+                }
               }
             },
-            "required": ["filename", "replaceWithEnv", "stringToReplace"]
+            "required": [
+              "filename",
+              "replaceWithFile",
+              "stringToReplace"
+            ]
           },
           {
             "type": "object",
             "additionalProperties": false,
             "properties": {
+              "replaceWithEnv": {
+                "type": "string"
+              },
+              "stringToReplace": {
+                "type": "string"
+              },
+              "filename": {
+                "type": "string"
+              },
               "replaceWhenEnv": {
                 "type": "array",
                 "items": {
@@ -248,30 +263,36 @@
                       "type": "string"
                     },
                     "value": {
-                      "type": ["string", "number", "boolean"]
+                      "type": "string"
                     }
                   },
-                  "required": ["env", "value"],
+                  "required": [
+                    "env",
+                    "value"
+                  ],
                   "additionalProperties": false
-                },
-                "maxItems": 1
-              },
-              "regexToReplace": {
-                "$ref": "#/definitions/replacements.regexToReplace"
-              },
-              "replaceWithEnv": {
-                "$ref": "#/definitions/replacements.replaceWithEnv"
-              },
-              "filename": {
-                "$ref": "#/definitions/replacements.filename"
+                }
               }
             },
-            "required": ["filename", "regexToReplace", "replaceWithEnv"]
+            "required": [
+              "filename",
+              "replaceWithEnv",
+              "stringToReplace"
+            ]
           },
           {
             "type": "object",
             "additionalProperties": false,
             "properties": {
+              "replaceWithFile": {
+                "type": "string"
+              },
+              "regexToReplace": {
+                "type": "string"
+              },
+              "filename": {
+                "type": "string"
+              },
               "replaceWhenEnv": {
                 "type": "array",
                 "items": {
@@ -281,29 +302,36 @@
                       "type": "string"
                     },
                     "value": {
-                      "type": ["string", "number", "boolean"]
+                      "type": "string"
                     }
                   },
-                  "required": ["env", "value"],
+                  "required": [
+                    "env",
+                    "value"
+                  ],
                   "additionalProperties": false
                 }
-              },
-              "stringToReplace": {
-                "$ref": "#/definitions/replacements.stringToReplace"
-              },
-              "replaceWithEnv": {
-                "$ref": "#/definitions/replacements.replaceWithEnv"
-              },
-              "filename": {
-                "$ref": "#/definitions/replacements.filename"
               }
             },
-            "required": ["filename", "replaceWithFile", "stringToReplace"]
+            "required": [
+              "filename",
+              "regexToReplace",
+              "replaceWithFile"
+            ]
           },
           {
             "type": "object",
             "additionalProperties": false,
             "properties": {
+              "replaceWithEnv": {
+                "type": "string"
+              },
+              "regexToReplace": {
+                "type": "string"
+              },
+              "filename": {
+                "type": "string"
+              },
               "replaceWhenEnv": {
                 "type": "array",
                 "items": {
@@ -313,30 +341,36 @@
                       "type": "string"
                     },
                     "value": {
-                      "type": ["string", "number", "boolean"]
+                      "type": "string"
                     }
                   },
-                  "required": ["env", "value"],
+                  "required": [
+                    "env",
+                    "value"
+                  ],
                   "additionalProperties": false
-                },
-                "maxItems": 1
-              },
-              "regexToReplace": {
-                "$ref": "#/definitions/replacements.regexToReplace"
-              },
-              "replaceWithFile": {
-                "$ref": "#/definitions/replacements.replaceWithFile"
-              },
-              "filename": {
-                "$ref": "#/definitions/replacements.filename"
+                }
               }
             },
-            "required": ["filename", "regexToReplace", "replaceWithFile"]
+            "required": [
+              "filename",
+              "regexToReplace",
+              "replaceWithEnv"
+            ]
           },
           {
             "type": "object",
             "additionalProperties": false,
             "properties": {
+              "replaceWithFile": {
+                "type": "string"
+              },
+              "stringToReplace": {
+                "type": "string"
+              },
+              "glob": {
+                "type": "string"
+              },
               "replaceWhenEnv": {
                 "type": "array",
                 "items": {
@@ -346,30 +380,36 @@
                       "type": "string"
                     },
                     "value": {
-                      "type": ["string", "number", "boolean"]
+                      "type": "string"
                     }
                   },
-                  "required": ["env", "value"],
+                  "required": [
+                    "env",
+                    "value"
+                  ],
                   "additionalProperties": false
-                },
-                "maxItems": 1
-              },
-              "stringToReplace": {
-                "$ref": "#/definitions/replacements.stringToReplace"
-              },
-              "replaceWithEnv": {
-                "$ref": "#/definitions/replacements.replaceWithEnv"
-              },
-              "glob": {
-                "$ref": "#/definitions/replacements.glob"
+                }
               }
             },
-            "required": ["glob", "replaceWithEnv", "stringToReplace"]
+            "required": [
+              "glob",
+              "replaceWithFile",
+              "stringToReplace"
+            ]
           },
           {
             "type": "object",
             "additionalProperties": false,
             "properties": {
+              "replaceWithEnv": {
+                "type": "string"
+              },
+              "stringToReplace": {
+                "type": "string"
+              },
+              "glob": {
+                "type": "string"
+              },
               "replaceWhenEnv": {
                 "type": "array",
                 "items": {
@@ -379,30 +419,36 @@
                       "type": "string"
                     },
                     "value": {
-                      "type": ["string", "number", "boolean"]
+                      "type": "string"
                     }
                   },
-                  "required": ["env", "value"],
+                  "required": [
+                    "env",
+                    "value"
+                  ],
                   "additionalProperties": false
-                },
-                "maxItems": 1
-              },
-              "regexToReplace": {
-                "$ref": "#/definitions/replacements.regexToReplace"
-              },
-              "replaceWithEnv": {
-                "$ref": "#/definitions/replacements.replaceWithEnv"
-              },
-              "glob": {
-                "$ref": "#/definitions/replacements.glob"
+                }
               }
             },
-            "required": ["glob", "regexToReplace", "replaceWithEnv"]
+            "required": [
+              "glob",
+              "replaceWithEnv",
+              "stringToReplace"
+            ]
           },
           {
             "type": "object",
             "additionalProperties": false,
             "properties": {
+              "replaceWithFile": {
+                "type": "string"
+              },
+              "regexToReplace": {
+                "type": "string"
+              },
+              "glob": {
+                "type": "string"
+              },
               "replaceWhenEnv": {
                 "type": "array",
                 "items": {
@@ -412,30 +458,36 @@
                       "type": "string"
                     },
                     "value": {
-                      "type": ["string", "number", "boolean"]
+                      "type": "string"
                     }
                   },
-                  "required": ["env", "value"],
+                  "required": [
+                    "env",
+                    "value"
+                  ],
                   "additionalProperties": false
-                },
-                "maxItems": 1
-              },
-              "stringToReplace": {
-                "$ref": "#/definitions/replacements.stringToReplace"
-              },
-              "replaceWithEnv": {
-                "$ref": "#/definitions/replacements.replaceWithEnv"
-              },
-              "glob": {
-                "$ref": "#/definitions/replacements.glob"
+                }
               }
             },
-            "required": ["glob", "replaceWithFile", "stringToReplace"]
+            "required": [
+              "glob",
+              "regexToReplace",
+              "replaceWithFile"
+            ]
           },
           {
             "type": "object",
             "additionalProperties": false,
             "properties": {
+              "replaceWithEnv": {
+                "type": "string"
+              },
+              "regexToReplace": {
+                "type": "string"
+              },
+              "glob": {
+                "type": "string"
+              },
               "replaceWhenEnv": {
                 "type": "array",
                 "items": {
@@ -445,25 +497,22 @@
                       "type": "string"
                     },
                     "value": {
-                      "type": ["string", "number", "boolean"]
+                      "type": "string"
                     }
                   },
-                  "required": ["env", "value"],
+                  "required": [
+                    "env",
+                    "value"
+                  ],
                   "additionalProperties": false
-                },
-                "maxItems": 1
-              },
-              "regexToReplace": {
-                "$ref": "#/definitions/replacements.regexToReplace"
-              },
-              "replaceWithFile": {
-                "$ref": "#/definitions/replacements.replaceWithFile"
-              },
-              "glob": {
-                "$ref": "#/definitions/replacements.glob"
+                }
               }
             },
-            "required": ["glob", "regexToReplace", "replaceWithFile"]
+            "required": [
+              "glob",
+              "regexToReplace",
+              "replaceWithEnv"
+            ]
           }
         ]
       }
@@ -679,4 +728,4 @@
       "description": "Use the contents of this file to replace the target"
     }
   }
-}
+}
\ No newline at end of file
diff --git a/src/replacements.ts b/src/replacements.ts
new file mode 100644
index 0000000..eff67ea
--- /dev/null
+++ b/src/replacements.ts
@@ -0,0 +1,28 @@
+export type Replacements = {
+  replaceWhenEnv?: Array<EnvConditional>;
+} & WhereToReplace &
+  WhatToReplace &
+  ReplaceWith;
+
+type WhereToReplace =
+  | { filename: string; glob?: never }
+  | { glob: string; filename?: never };
+
+type WhatToReplace =
+  | {
+      stringToReplace: string;
+      regexToReplace?: never;
+    }
+  | { regexToReplace: string; stringToReplace?: never };
+
+type ReplaceWith =
+  | {
+      replaceWithFile: string;
+      replaceWithEnv?: never;
+    }
+  | { replaceWithEnv: string; replaceWithFile?: never };
+
+type EnvConditional = {
+  env: string;
+  value: string;
+};
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..dcfebe2
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,9 @@
+{
+  "extends": "./node_modules/@salesforce/dev-config/tsconfig-strict",
+  "compilerOptions": {
+    "outDir": "./lib",
+    "skipLibCheck": true,
+    "strictNullChecks": true
+  },
+  "include": ["src/**/*.ts"]
+}
diff --git a/yarn.lock b/yarn.lock
index 238808c..2a596d3 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -501,6 +501,11 @@
     mkdirp "^0.5.1"
     rimraf "^2.5.2"
 
+"@salesforce/dev-config@^3.1.0":
+  version "3.1.0"
+  resolved "https://registry.yarnpkg.com/@salesforce/dev-config/-/dev-config-3.1.0.tgz#8eb5b35860ff60d1c1dc3fd9329b01a28475d5b9"
+  integrity sha512-cPph7ibj3DeSzWDFLcLtxOh5fmUlDUY2Ezq43n0V6auVP+l8orxRHjCExHS86SB3QKVgXkC8yYhryXiS8KF7Zw==
+
 "@types/babel__core@^7.1.0":
   version "7.1.6"
   resolved "https://registry.yarnpkg.com/@types/babel__core/-/babel__core-7.1.6.tgz#16ff42a5ae203c9af1c6e190ed1f30f83207b610"