diff --git a/package-lock.json b/package-lock.json
index 8ad5e445d6..374e140a7b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -35,7 +35,7 @@
         "@types/uuid": "^10.0.0",
         "eslint": "^8.56.0",
         "eslint-config-next": "^15.0.1",
-        "fast-check": "^3.15.0",
+        "fast-check": "^4.0.1",
         "jest": "^29.7.0",
         "jest-environment-jsdom": "^29.7.0",
         "prettier": "3.5.3",
@@ -5043,9 +5043,9 @@
       }
     },
     "node_modules/fast-check": {
-      "version": "3.15.0",
-      "resolved": "https://registry.npmjs.org/fast-check/-/fast-check-3.15.0.tgz",
-      "integrity": "sha512-iBz6c+EXL6+nI931x/sbZs1JYTZtLG6Cko0ouS8LRTikhDR7+wZk4TYzdRavlnByBs2G6+nuuJ7NYL9QplNt8Q==",
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/fast-check/-/fast-check-4.0.1.tgz",
+      "integrity": "sha512-Z91jcH02ySQBQlKrCIs3tKTEHdkzOqQhHW5Mg4aZRo4lbI39a28jrFlik6FaRUNzm823VDDTtAi5AEV6lZZprQ==",
       "dev": true,
       "funding": [
         {
@@ -5057,13 +5057,31 @@
           "url": "https://opencollective.com/fast-check"
         }
       ],
+      "license": "MIT",
       "dependencies": {
-        "pure-rand": "^6.0.0"
+        "pure-rand": "^7.0.0"
       },
       "engines": {
-        "node": ">=8.0.0"
+        "node": ">=12.17.0"
       }
     },
+    "node_modules/fast-check/node_modules/pure-rand": {
+      "version": "7.0.1",
+      "resolved": "https://registry.npmjs.org/pure-rand/-/pure-rand-7.0.1.tgz",
+      "integrity": "sha512-oTUZM/NAZS8p7ANR3SHh30kXB+zK2r2BPcEn/awJIbOvq82WoMN4p62AWWp3Hhw50G0xMsw1mhIBLqHw64EcNQ==",
+      "dev": true,
+      "funding": [
+        {
+          "type": "individual",
+          "url": "https://github.com/sponsors/dubzzz"
+        },
+        {
+          "type": "opencollective",
+          "url": "https://opencollective.com/fast-check"
+        }
+      ],
+      "license": "MIT"
+    },
     "node_modules/fast-deep-equal": {
       "version": "3.1.3",
       "resolved": "https://registry.npmjs.org/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz",
@@ -13826,12 +13844,20 @@
       }
     },
     "fast-check": {
-      "version": "3.15.0",
-      "resolved": "https://registry.npmjs.org/fast-check/-/fast-check-3.15.0.tgz",
-      "integrity": "sha512-iBz6c+EXL6+nI931x/sbZs1JYTZtLG6Cko0ouS8LRTikhDR7+wZk4TYzdRavlnByBs2G6+nuuJ7NYL9QplNt8Q==",
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/fast-check/-/fast-check-4.0.1.tgz",
+      "integrity": "sha512-Z91jcH02ySQBQlKrCIs3tKTEHdkzOqQhHW5Mg4aZRo4lbI39a28jrFlik6FaRUNzm823VDDTtAi5AEV6lZZprQ==",
       "dev": true,
       "requires": {
-        "pure-rand": "^6.0.0"
+        "pure-rand": "^7.0.0"
+      },
+      "dependencies": {
+        "pure-rand": {
+          "version": "7.0.1",
+          "resolved": "https://registry.npmjs.org/pure-rand/-/pure-rand-7.0.1.tgz",
+          "integrity": "sha512-oTUZM/NAZS8p7ANR3SHh30kXB+zK2r2BPcEn/awJIbOvq82WoMN4p62AWWp3Hhw50G0xMsw1mhIBLqHw64EcNQ==",
+          "dev": true
+        }
       }
     },
     "fast-deep-equal": {
diff --git a/package.json b/package.json
index 29e054c01a..1fcd128d2d 100644
--- a/package.json
+++ b/package.json
@@ -186,7 +186,7 @@
     "@types/uuid": "^10.0.0",
     "eslint": "^8.56.0",
     "eslint-config-next": "^15.0.1",
-    "fast-check": "^3.15.0",
+    "fast-check": "^4.0.1",
     "jest": "^29.7.0",
     "jest-environment-jsdom": "^29.7.0",
     "prettier": "3.5.3",
diff --git a/src/rdf.test.ts b/src/rdf.test.ts
index b4ec342194..616e8253ce 100644
--- a/src/rdf.test.ts
+++ b/src/rdf.test.ts
@@ -91,7 +91,7 @@ describe("fromRdfJsDataset", () => {
     fcArbitraryLiteral,
   );
   const fcBlankNode = fc
-    .asciiString()
+    .string()
     .map((asciiString) => DF.blankNode(asciiString));
   const fcDefaultGraph = fc.constant(DF.defaultGraph());
   const fcGraph = fc.oneof(fcDefaultGraph, fcNamedNode);
@@ -600,9 +600,20 @@ describe("toRdfJsDataset", () => {
       fc.uniqueArray(fc.string(), { minLength: 1 }),
     )
     .filter(isNotEmpty);
+  // Replaced deprecated hexaString with custom implementation for v4
+  const hexaChars = "0123456789abcdef";
+  const hexa = () => {
+    return fc.integer({ min: 0, max: 15 }).map(
+      (n) => hexaChars[n],
+      (c) => hexaChars.indexOf(<string>c),
+    );
+  };
+  const hexaString = (constraints: fc.StringConstraints = {}) =>
+    fc.string({ ...constraints, unit: hexa() });
+
   const fcLangStrings = fc
     .dictionary(
-      fc.hexaString({ minLength: 1 }).map((str) => str.toLowerCase()),
+      hexaString({ minLength: 1 }).map((str) => str.toLowerCase()),
       fc.uniqueArray(fc.string(), { minLength: 1 }),
     )
     .filter(isNotEmpty);
@@ -619,16 +630,28 @@ describe("toRdfJsDataset", () => {
       minLength: 1,
     },
   );
+  // withDeletedKeys option was removed in v4, achieve similar functionality with filter
   const fcObjects = fc
-    .record(
-      {
-        literals: fcLiterals,
-        langStrings: fcLangStrings,
-        namedNodes: fcNamedNodes,
-        // blankNodes: fcBlankNodes,
-      },
-      { withDeletedKeys: true },
-    )
+    .record({
+      literals: fcLiterals,
+      langStrings: fcLangStrings,
+      namedNodes: fcNamedNodes,
+      // blankNodes: fcBlankNodes,
+    })
+    .map((obj) => {
+      // Randomly delete some keys to achieve similar behavior to withDeletedKeys
+      const keys = Object.keys(obj) as Array<keyof typeof obj>;
+      if (keys.length <= 1) return obj; // Keep at least one property
+
+      const result = { ...obj };
+      // Delete random keys with 50% chance for each
+      keys.forEach((key) => {
+        if (Math.random() < 0.5 && Object.keys(result).length > 1) {
+          delete result[key];
+        }
+      });
+      return result;
+    })
     .filter(isNotEmpty);
   // Unfortunately I haven't figured out how to generate the nested blank node
   // structures with fast-check yet, so this does not generate those: