diff --git a/ext/fetch/23_request.js b/ext/fetch/23_request.js
index adebe13b30..6211e927d9 100644
--- a/ext/fetch/23_request.js
+++ b/ext/fetch/23_request.js
@@ -122,7 +122,7 @@ function newInnerRequest(method, url, headerList, body, maybeBlob) {
         try {
           this.headerListInner = headerList();
         } catch {
-          throw new TypeError("cannot read headers: request closed");
+          throw new TypeError("Cannot read headers: request closed");
         }
       }
       return this.headerListInner;
@@ -153,7 +153,7 @@ function newInnerRequest(method, url, headerList, body, maybeBlob) {
         try {
           this.urlListProcessed[currentIndex] = this.urlList[currentIndex]();
         } catch {
-          throw new TypeError("cannot read url: request closed");
+          throw new TypeError("Cannot read url: request closed");
         }
       }
       return this.urlListProcessed[currentIndex];
@@ -193,7 +193,7 @@ function cloneInnerRequest(request, skipBody = false) {
         try {
           this.urlListProcessed[0] = this.urlList[0]();
         } catch {
-          throw new TypeError("cannot read url: request closed");
+          throw new TypeError("Cannot read url: request closed");
         }
       }
       return this.urlListProcessed[0];
@@ -204,7 +204,7 @@ function cloneInnerRequest(request, skipBody = false) {
         try {
           this.urlListProcessed[currentIndex] = this.urlList[currentIndex]();
         } catch {
-          throw new TypeError("cannot read url: request closed");
+          throw new TypeError("Cannot read url: request closed");
         }
       }
       return this.urlListProcessed[currentIndex];
@@ -236,13 +236,13 @@ const KNOWN_METHODS = {
  */
 function validateAndNormalizeMethod(m) {
   if (RegExpPrototypeExec(HTTP_TOKEN_CODE_POINT_RE, m) === null) {
-    throw new TypeError("Method is not valid.");
+    throw new TypeError("Method is not valid");
   }
   const upperCase = byteUpperCase(m);
   if (
     upperCase === "CONNECT" || upperCase === "TRACE" || upperCase === "TRACK"
   ) {
-    throw new TypeError("Method is forbidden.");
+    throw new TypeError("Method is forbidden");
   }
   return upperCase;
 }
@@ -418,7 +418,7 @@ class Request {
       ((init.body !== undefined && init.body !== null) ||
         inputBody !== null)
     ) {
-      throw new TypeError("Request with GET/HEAD method cannot have body.");
+      throw new TypeError("Request with GET/HEAD method cannot have body");
     }
 
     // 36.
@@ -442,7 +442,7 @@ class Request {
     // 41.
     if (initBody === null && inputBody !== null) {
       if (input[_body] && input[_body].unusable()) {
-        throw new TypeError("Input request's body is unusable.");
+        throw new TypeError("Input request's body is unusable");
       }
       finalBody = inputBody.createProxy();
     }
@@ -489,7 +489,7 @@ class Request {
     const prefix = "Failed to execute 'Request.clone'";
     webidl.assertBranded(this, RequestPrototype);
     if (this[_body] && this[_body].unusable()) {
-      throw new TypeError("Body is unusable.");
+      throw new TypeError("Body is unusable");
     }
     const clonedReq = cloneInnerRequest(this[_request]);
 
diff --git a/ext/http/00_serve.ts b/ext/http/00_serve.ts
index 6d23685d8e..3b9b085a22 100644
--- a/ext/http/00_serve.ts
+++ b/ext/http/00_serve.ts
@@ -123,7 +123,7 @@ function upgradeHttpRaw(req, conn) {
   if (inner._wantsUpgrade) {
     return inner._wantsUpgrade("upgradeHttpRaw", conn);
   }
-  throw new TypeError("upgradeHttpRaw may only be used with Deno.serve");
+  throw new TypeError("'upgradeHttpRaw' may only be used with Deno.serve");
 }
 
 function addTrailers(resp, headerList) {
@@ -170,10 +170,10 @@ class InnerRequest {
 
   _wantsUpgrade(upgradeType, ...originalArgs) {
     if (this.#upgraded) {
-      throw new Deno.errors.Http("already upgraded");
+      throw new Deno.errors.Http("Already upgraded");
     }
     if (this.#external === null) {
-      throw new Deno.errors.Http("already closed");
+      throw new Deno.errors.Http("Already closed");
     }
 
     // upgradeHttpRaw is sync
@@ -257,7 +257,7 @@ class InnerRequest {
 
     if (this.#methodAndUri === undefined) {
       if (this.#external === null) {
-        throw new TypeError("request closed");
+        throw new TypeError("Request closed");
       }
       // TODO(mmastrac): This is quite slow as we're serializing a large number of values. We may want to consider
       // splitting this up into multiple ops.
@@ -315,7 +315,7 @@ class InnerRequest {
     }
     if (this.#methodAndUri === undefined) {
       if (this.#external === null) {
-        throw new TypeError("request closed");
+        throw new TypeError("Request closed");
       }
       this.#methodAndUri = op_http_get_request_method_and_url(this.#external);
     }
@@ -329,7 +329,7 @@ class InnerRequest {
   get method() {
     if (this.#methodAndUri === undefined) {
       if (this.#external === null) {
-        throw new TypeError("request closed");
+        throw new TypeError("Request closed");
       }
       this.#methodAndUri = op_http_get_request_method_and_url(this.#external);
     }
@@ -338,7 +338,7 @@ class InnerRequest {
 
   get body() {
     if (this.#external === null) {
-      throw new TypeError("request closed");
+      throw new TypeError("Request closed");
     }
     if (this.#body !== undefined) {
       return this.#body;
@@ -356,7 +356,7 @@ class InnerRequest {
 
   get headerList() {
     if (this.#external === null) {
-      throw new TypeError("request closed");
+      throw new TypeError("Request closed");
     }
     const headers = [];
     const reqHeaders = op_http_get_request_headers(this.#external);
@@ -457,7 +457,7 @@ function fastSyncResponseOrStream(
   // At this point in the response it needs to be a stream
   if (!ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, stream)) {
     innerRequest?.close();
-    throw new TypeError("invalid response");
+    throw new TypeError("Invalid response");
   }
   const resourceBacking = getReadableStreamResourceBacking(stream);
   let rid, autoClose;
@@ -619,13 +619,15 @@ function serve(arg1, arg2) {
   if (handler === undefined) {
     if (options === undefined) {
       throw new TypeError(
-        "No handler was provided, so an options bag is mandatory.",
+        "Cannot serve HTTP requests: either a `handler` or `options` must be specified",
       );
     }
     handler = options.handler;
   }
   if (typeof handler !== "function") {
-    throw new TypeError("A handler function must be provided.");
+    throw new TypeError(
+      `Cannot serve HTTP requests: handler must be a function, received ${typeof handler}`,
+    );
   }
   if (options === undefined) {
     options = { __proto__: null };
@@ -679,7 +681,7 @@ function serve(arg1, arg2) {
   if (wantsHttps) {
     if (!options.cert || !options.key) {
       throw new TypeError(
-        "Both cert and key must be provided to enable HTTPS.",
+        "Both 'cert' and 'key' must be provided to enable HTTPS",
       );
     }
     listenOpts.cert = options.cert;
diff --git a/ext/http/01_http.js b/ext/http/01_http.js
index e886848581..9302bd8a0f 100644
--- a/ext/http/01_http.js
+++ b/ext/http/01_http.js
@@ -207,7 +207,7 @@ function createRespondWith(
       resp = await resp;
       if (!(ObjectPrototypeIsPrototypeOf(ResponsePrototype, resp))) {
         throw new TypeError(
-          "First argument to respondWith must be a Response or a promise resolving to a Response.",
+          "First argument to 'respondWith' must be a Response or a promise resolving to a Response",
         );
       }
 
@@ -220,7 +220,7 @@ function createRespondWith(
       let respBody = null;
       if (innerResp.body !== null) {
         if (innerResp.body.unusable()) {
-          throw new TypeError("Body is unusable.");
+          throw new TypeError("Body is unusable");
         }
         if (
           ObjectPrototypeIsPrototypeOf(
@@ -295,7 +295,7 @@ function createRespondWith(
         let reader;
         if (resourceBacking) {
           if (respBody.locked) {
-            throw new TypeError("ReadableStream is locked.");
+            throw new TypeError("ReadableStream is locked");
           }
           reader = respBody.getReader(); // Acquire JS lock.
           try {
diff --git a/tests/unit/serve_test.ts b/tests/unit/serve_test.ts
index d417d8d268..439d71d553 100644
--- a/tests/unit/serve_test.ts
+++ b/tests/unit/serve_test.ts
@@ -1592,7 +1592,7 @@ Deno.test(
             Deno.upgradeWebSocket(request);
           },
           Deno.errors.Http,
-          "already upgraded",
+          "Already upgraded",
         );
         socket.onerror = (e) => {
           console.error(e);
@@ -3694,7 +3694,7 @@ Deno.test(
         } catch (cloneError) {
           assert(cloneError instanceof TypeError);
           assert(
-            cloneError.message.endsWith("Body is unusable."),
+            cloneError.message.endsWith("Body is unusable"),
           );
 
           ac.abort();
@@ -3743,7 +3743,7 @@ Deno.test({
         } catch (cloneError) {
           assert(cloneError instanceof TypeError);
           assert(
-            cloneError.message.endsWith("Body is unusable."),
+            cloneError.message.endsWith("Body is unusable"),
           );
 
           ac.abort();
@@ -3895,7 +3895,7 @@ async function readTrailers(
   const tp = new TextProtoReader(r);
   const result = await tp.readMimeHeader();
   if (result == null) {
-    throw new Deno.errors.InvalidData("Missing trailer header.");
+    throw new Deno.errors.InvalidData("Missing trailer header");
   }
   const undeclared = [...result.keys()].filter(
     (k) => !trailerNames.includes(k),
@@ -3923,7 +3923,7 @@ function parseTrailer(field: string | null): Headers | undefined {
   }
   const trailerNames = field.split(",").map((v) => v.trim().toLowerCase());
   if (trailerNames.length === 0) {
-    throw new Deno.errors.InvalidData("Empty trailer header.");
+    throw new Deno.errors.InvalidData("Empty trailer header");
   }
   const prohibited = trailerNames.filter((k) => isProhibitedForTrailer(k));
   if (prohibited.length > 0) {