diff --git a/package-lock.json b/package-lock.json
index 776cbd5..5fabac0 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -14,6 +14,7 @@
         "@fortawesome/free-solid-svg-icons": "^6.5.1",
         "@fortawesome/react-fontawesome": "^0.2.0",
         "@hookform/resolvers": "^3.3.2",
+        "@monaco-editor/react": "^4.6.0",
         "@radix-ui/react-collapsible": "^1.0.3",
         "@radix-ui/react-dialog": "^1.0.5",
         "@radix-ui/react-label": "^2.0.2",
@@ -4070,6 +4071,30 @@
         "@jridgewell/sourcemap-codec": "^1.4.14"
       }
     },
+    "node_modules/@monaco-editor/loader": {
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/@monaco-editor/loader/-/loader-1.4.0.tgz",
+      "integrity": "sha512-00ioBig0x642hytVspPl7DbQyaSWRaolYie/UFNjoTdvoKPzo6xrXLhTk9ixgIKcLH5b5vDOjVNiGyY+uDCUlg==",
+      "dependencies": {
+        "state-local": "^1.0.6"
+      },
+      "peerDependencies": {
+        "monaco-editor": ">= 0.21.0 < 1"
+      }
+    },
+    "node_modules/@monaco-editor/react": {
+      "version": "4.6.0",
+      "resolved": "https://registry.npmjs.org/@monaco-editor/react/-/react-4.6.0.tgz",
+      "integrity": "sha512-RFkU9/i7cN2bsq/iTkurMWOEErmYcY6JiQI3Jn+WeR/FGISH8JbHERjpS9oRuSOPvDMJI0Z8nJeKkbOs9sBYQw==",
+      "dependencies": {
+        "@monaco-editor/loader": "^1.4.0"
+      },
+      "peerDependencies": {
+        "monaco-editor": ">= 0.25.0 < 1",
+        "react": "^16.8.0 || ^17.0.0 || ^18.0.0",
+        "react-dom": "^16.8.0 || ^17.0.0 || ^18.0.0"
+      }
+    },
     "node_modules/@nodelib/fs.scandir": {
       "version": "2.1.5",
       "resolved": "https://registry.npmjs.org/@nodelib/fs.scandir/-/fs.scandir-2.1.5.tgz",
@@ -11593,6 +11618,12 @@
         "node": ">=16 || 14 >=14.17"
       }
     },
+    "node_modules/monaco-editor": {
+      "version": "0.47.0",
+      "resolved": "https://registry.npmjs.org/monaco-editor/-/monaco-editor-0.47.0.tgz",
+      "integrity": "sha512-VabVvHvQ9QmMwXu4du008ZDuyLnHs9j7ThVFsiJoXSOQk18+LF89N4ADzPbFenm0W4V2bGHnFBztIRQTgBfxzw==",
+      "peer": true
+    },
     "node_modules/ms": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
@@ -13143,6 +13174,11 @@
         "node": ">=8"
       }
     },
+    "node_modules/state-local": {
+      "version": "1.0.7",
+      "resolved": "https://registry.npmjs.org/state-local/-/state-local-1.0.7.tgz",
+      "integrity": "sha512-HTEHMNieakEnoe33shBYcZ7NX83ACUjCu8c40iOGEZsngj9zRnkqS9j1pqQPXwobB0ZcVTk27REb7COQ0UR59w=="
+    },
     "node_modules/stop-iteration-iterator": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/stop-iteration-iterator/-/stop-iteration-iterator-1.0.0.tgz",
diff --git a/package.json b/package.json
index e275123..36eb1f2 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,7 @@
     "@fortawesome/free-solid-svg-icons": "^6.5.1",
     "@fortawesome/react-fontawesome": "^0.2.0",
     "@hookform/resolvers": "^3.3.2",
+    "@monaco-editor/react": "^4.6.0",
     "@radix-ui/react-collapsible": "^1.0.3",
     "@radix-ui/react-dialog": "^1.0.5",
     "@radix-ui/react-label": "^2.0.2",
diff --git a/src/entities/http-for-dummies.ts b/src/entities/http-for-dummies.ts
index d3cfddf..da9334c 100644
--- a/src/entities/http-for-dummies.ts
+++ b/src/entities/http-for-dummies.ts
@@ -14,6 +14,10 @@ export function isRequestingToLocalhost(request: RequestSnapshot): boolean {
   ].some((localBeginning) => request.url.startsWith(localBeginning));
 }
 
+export function canMethodHaveBody(method: RequestSnapshot["method"]): boolean {
+  return method !== "GET" && method !== "HEAD";
+}
+
 /** HTTP methods but as constants. */
 export const HTTP_METHODS: ProjectRequestSpec["method"][] = [
   "GET",
diff --git a/src/entities/runtime-entities.ts b/src/entities/runtime-entities.ts
index a0ec853..2ea849b 100644
--- a/src/entities/runtime-entities.ts
+++ b/src/entities/runtime-entities.ts
@@ -32,7 +32,7 @@ export interface RuntimeState {
 export interface RequestSnapshot {
   readonly url: string;
   readonly method: string;
-  readonly body: string;
+  readonly body: string | null;
   readonly headers: { key: string; value: string }[];
 }
 
diff --git a/src/features/project-workspace/BodyEditor.tsx b/src/features/project-workspace/BodyEditor.tsx
new file mode 100644
index 0000000..5249435
--- /dev/null
+++ b/src/features/project-workspace/BodyEditor.tsx
@@ -0,0 +1,39 @@
+import { Editor, EditorProps } from "@monaco-editor/react";
+import { useCallback, useId } from "react";
+
+export interface BodyEditorProps extends Omit<EditorProps, "onMount"> {
+  name: string;
+}
+
+export function BodyEditor(props: BodyEditorProps) {
+  const id = useId();
+
+  const { name, wrapperProps, ...restOfProps } = props;
+  const overridingWrapperProps = { ...wrapperProps, id };
+
+  const handleOnMount = useCallback(() => {
+    const wrapperEl = document.getElementById(id);
+    if (!wrapperEl) {
+      throw new Error("Unexpected missing wrapper during `BodyEditor` mount.");
+    }
+
+    const [textareaEl] = wrapperEl.getElementsByTagName("textarea");
+    if (!textareaEl) {
+      throw new Error(
+        "Unexpected missing `textarea` during `BodyEditor` mount."
+      );
+    }
+
+    textareaEl.setAttribute("name", name);
+  }, [id, name]);
+
+  return (
+    <Editor
+      language="json"
+      theme="vs-dark"
+      {...restOfProps}
+      wrapperProps={overridingWrapperProps}
+      onMount={handleOnMount}
+    />
+  );
+}
diff --git a/src/features/project-workspace/Runtime.test.tsx b/src/features/project-workspace/Runtime.test.tsx
index 0558a76..55ffd96 100644
--- a/src/features/project-workspace/Runtime.test.tsx
+++ b/src/features/project-workspace/Runtime.test.tsx
@@ -13,8 +13,25 @@ jest.mock("@/services/opfs-projects-shared-internals", () => ({
   persistProject: jest.fn(),
 }));
 
+jest.mock("./BodyEditor.tsx", () => ({
+  BodyEditor: jest
+    .fn()
+    .mockImplementation(({ name, defaultValue, onChange }) => (
+      <div id="mocked-body-editor">
+        <textarea
+          name={name}
+          defaultValue={defaultValue}
+          onChange={(e) => onChange(e.target.value)}
+        />
+      </div>
+    )),
+}));
+
 interface MockedGlobalWithFetch {
-  fetch: (url: string) => Promise<MockedResponse>;
+  fetch: (
+    url: string,
+    options: { body: string; method: string }
+  ) => Promise<MockedResponse>;
 }
 
 interface MockedResponse {
@@ -80,6 +97,24 @@ describe("Runtime component, given a selected specification", () => {
             ],
             body: "",
           },
+          {
+            uuid: "f4eb2eec-3527-4d96-b34a-cc0e9914231c",
+            url: "https://echo.zuplo.io/",
+            method: "POST",
+            headers: [
+              { key: "Accept", value: "application/json", isEnabled: true },
+            ],
+            body: JSON.stringify({ "this is": "an echo test" }),
+          },
+          {
+            uuid: "894f6e21-8002-4111-938b-dbebaaa44966",
+            url: "https://echo.zuplo.io/",
+            method: "GET",
+            headers: [
+              { key: "Accept", value: "application/json", isEnabled: true },
+            ],
+            body: JSON.stringify({ "this is": "an echo test" }),
+          },
         ],
       });
 
@@ -89,7 +124,14 @@ describe("Runtime component, given a selected specification", () => {
 
     jest
       .spyOn(global as unknown as MockedGlobalWithFetch, "fetch")
-      .mockImplementation(async (url: string) => {
+      .mockImplementation(async (url, { body, method }) => {
+        if ((method === "GET" || method === "HEAD") && body !== null) {
+          // same behavior as Chrome
+          throw new Error(
+            "Failed to execute 'fetch' on 'Window': Request with GET/HEAD method cannot have body."
+          );
+        }
+
         switch (url) {
           case "https://api.zippopotam.us/us/33162":
             return {
@@ -148,6 +190,15 @@ describe("Runtime component, given a selected specification", () => {
           case "https://catfact.ninja/non-existing":
             throw new Error("CORS Error (mocked).");
 
+          case "https://echo.zuplo.io/":
+            // this is similar but not exactly the same behavior as this Echo API
+            return {
+              text: async () => body,
+              status: 200,
+              ok: true,
+              headers: [["content-type", "application/json"]],
+            };
+
           default:
             throw new Error(
               "Unexpected `fetch` call during test scenario. Unmocked URL."
@@ -230,6 +281,32 @@ describe("Runtime component, given a selected specification", () => {
           ],
           body: "",
         },
+        {
+          body: '{"this is":"an echo test"}',
+          headers: [
+            {
+              isEnabled: true,
+              key: "Accept",
+              value: "application/json",
+            },
+          ],
+          method: "POST",
+          url: "https://echo.zuplo.io/",
+          uuid: "f4eb2eec-3527-4d96-b34a-cc0e9914231c",
+        },
+        {
+          body: '{"this is":"an echo test"}',
+          headers: [
+            {
+              isEnabled: true,
+              key: "Accept",
+              value: "application/json",
+            },
+          ],
+          method: "GET",
+          url: "https://echo.zuplo.io/",
+          uuid: "894f6e21-8002-4111-938b-dbebaaa44966",
+        },
       ],
     });
   });
@@ -374,4 +451,62 @@ describe("Runtime component, given a selected specification", () => {
     expect(screen.getByText("Error")).toBeVisible();
     expect(screen.getByText(/CORS Error/im)).toBeVisible();
   });
+
+  it("can perform a POST using a body", async () => {
+    await act(async () =>
+      render(
+        <RequestsSpecsContextProvider projectUuid="7fde4f8e-b6ac-4218-ae20-1b866e61ec56">
+          <Runtime specUuid="f4eb2eec-3527-4d96-b34a-cc0e9914231c" />
+        </RequestsSpecsContextProvider>
+      )
+    );
+
+    const input = screen.getByText(/an echo test/, { selector: "textarea" });
+    expect(input).toBeVisible();
+
+    const run = screen.getByRole("button", { name: /Run/i });
+    await act(async () => fireEvent.click(run));
+
+    expect(screen.getByText(/HTTP success/i)).toBeVisible();
+    expect(screen.getByText("200")).toBeVisible();
+
+    const output = screen.getByText(/an echo test/, { selector: "code" });
+    expect(output).toBeVisible();
+
+    expect(global.fetch as jest.Mock).toHaveBeenCalledWith(
+      "https://echo.zuplo.io/",
+      {
+        body: '{"this is":"an echo test"}',
+        headers: { Accept: "application/json" },
+        method: "POST",
+      }
+    );
+  });
+
+  it("can perform a GET using a body, even if it throws an error", async () => {
+    await act(async () =>
+      render(
+        <RequestsSpecsContextProvider projectUuid="7fde4f8e-b6ac-4218-ae20-1b866e61ec56">
+          <Runtime specUuid="894f6e21-8002-4111-938b-dbebaaa44966" />
+        </RequestsSpecsContextProvider>
+      )
+    );
+
+    const run = screen.getByRole("button", { name: /Run/i });
+    await act(async () => fireEvent.click(run));
+
+    expect(screen.queryByText(/HTTP success/i)).toBe(null);
+    expect(screen.queryByText("200")).toBe(null);
+
+    expect(screen.getByText("Error")).toBeVisible();
+
+    expect(global.fetch as jest.Mock).toHaveBeenCalledWith(
+      "https://echo.zuplo.io/",
+      {
+        body: '{"this is":"an echo test"}',
+        headers: { Accept: "application/json" },
+        method: "GET",
+      }
+    );
+  });
 });
diff --git a/src/features/project-workspace/Runtime.tsx b/src/features/project-workspace/Runtime.tsx
index 249a3e7..d2ed951 100644
--- a/src/features/project-workspace/Runtime.tsx
+++ b/src/features/project-workspace/Runtime.tsx
@@ -38,12 +38,14 @@ import {
 } from "@/components/ui/dialog";
 import {
   HTTP_METHODS,
+  canMethodHaveBody,
   getMethodExplanation,
   getStatusExplanation,
   getStatusText,
   isRequestingToLocalhost,
 } from "../../entities/http-for-dummies";
 import { useRequestsSpecs } from "./RequestsSpecsContext";
+import { BodyEditor, BodyEditorProps } from "./BodyEditor";
 
 export interface RuntimeProps {
   specUuid: ProjectRequestSpec["uuid"];
@@ -53,6 +55,21 @@ export function Runtime(props: RuntimeProps) {
   const { specs, patch } = useRequestsSpecs();
   const spec = specs.find((s) => s.uuid === props.specUuid) ?? null;
 
+  // method
+
+  const patchMethod = (method: string) => {
+    if (!spec) {
+      throw new Error("Unexpected missing spec.");
+    }
+
+    patch({
+      uuid: spec.uuid,
+      method: method as ProjectRequestSpec["method"],
+    }).catch(console.error);
+  };
+
+  // url
+
   const patchUrlUnsafelly = (patching: { uuid: string; url: string }) => {
     patch(patching).catch(console.error);
   };
@@ -68,15 +85,21 @@ export function Runtime(props: RuntimeProps) {
     patchUrl(url);
   };
 
-  const patchMethod = (method: string) => {
-    if (!spec) {
-      throw new Error("Unexpected missing spec.");
-    }
+  // body
 
-    patch({
-      uuid: spec.uuid,
-      method: method as ProjectRequestSpec["method"],
-    }).catch(console.error);
+  const patchBodyUnsafelly = (patching: { uuid: string; body: string }) => {
+    patch(patching).catch(console.error);
+  };
+
+  const patchBodyRef = useRef<typeof patchBodyUnsafelly>(
+    debounce(patchBodyUnsafelly, 1000)
+  );
+
+  const patchBody = (body: string) =>
+    spec ? patchBodyRef.current({ uuid: spec.uuid, body }) : null;
+
+  const handleBodyChange: BodyEditorProps["onChange"] = (value) => {
+    patchBody(value ?? "");
   };
 
   const [runtime, setRuntime] = useState<RuntimeState>({
@@ -135,7 +158,11 @@ export function Runtime(props: RuntimeProps) {
       finishedAt: Date.now(),
     }));
 
-  const runSpec = async (running: { method: string; url: string }) => {
+  const runSpec = async (running: {
+    method: string;
+    url: string;
+    body: string;
+  }) => {
     if (!spec) {
       throw new Error("Unexpected missing spec.");
     }
@@ -143,7 +170,9 @@ export function Runtime(props: RuntimeProps) {
     const requestInfo: RequestSnapshot = {
       url: running.url,
       method: running.method,
-      body: "",
+      body: canMethodHaveBody(running.method)
+        ? running.body
+        : running.body || null,
       headers: spec.headers.length
         ? spec.headers.filter((h) => h.isEnabled)
         : [],
@@ -156,6 +185,7 @@ export function Runtime(props: RuntimeProps) {
     try {
       const response = await fetch(running.url, {
         method: requestInfo.method,
+        body: requestInfo.body,
         headers: requestInfo.headers.reduce(
           (headers, header) => ({ ...headers, [header.key]: header.value }),
           {}
@@ -189,57 +219,76 @@ export function Runtime(props: RuntimeProps) {
   const handleSubmit = (event: React.FormEvent<HTMLFormElement>) => {
     event.preventDefault();
 
+    // basic, hence requireds
     const method = (
       event.currentTarget.elements.namedItem("method") as HTMLInputElement
     ).value;
     const url = (
       event.currentTarget.elements.namedItem("url") as HTMLInputElement
     ).value;
-    runSpec({ method, url }).catch(console.error);
+
+    // not so basic, hence optional
+    const body = (
+      event.currentTarget.elements.namedItem("body") as HTMLTextAreaElement
+    ).value;
+
+    // aw yeah
+    runSpec({ method, url, body }).catch(console.error);
   };
 
   return (
     <section className="flex flex-col flex-grow px-5 py-3 border-2 h-full">
-      <form className="flex" onSubmit={handleSubmit}>
-        <Select
-          defaultValue={spec.method}
-          name="method"
-          onValueChange={patchMethod}
-          required
-        >
-          <SelectTrigger aria-label="Method" className="w-[120px]">
-            <SelectValue />
-          </SelectTrigger>
-          <SelectContent>
-            {HTTP_METHODS.map((method) => (
-              <SelectItem
-                key={method}
-                value={method}
-                title={getMethodExplanation(method)}
-              >
-                {method}
-              </SelectItem>
-            ))}
-          </SelectContent>
-        </Select>
-        <Input
-          type="url"
-          aria-label="URL"
-          name="url"
-          placeholder="Enter URL here..."
-          autoComplete="off"
-          spellCheck={false}
-          maxLength={2083}
-          className="mx-3 w-full"
-          defaultValue={spec.url || ""}
-          onChange={handleUrlChange}
-          required
-        />
-        <Button type="submit" className="px-10">
-          Run
-        </Button>
+      <form onSubmit={handleSubmit}>
+        <div className="flex">
+          <Select
+            defaultValue={spec.method}
+            name="method"
+            onValueChange={patchMethod}
+            required
+          >
+            <SelectTrigger aria-label="Method" className="w-[120px]">
+              <SelectValue />
+            </SelectTrigger>
+            <SelectContent>
+              {HTTP_METHODS.map((method) => (
+                <SelectItem
+                  key={method}
+                  value={method}
+                  title={getMethodExplanation(method)}
+                >
+                  {method}
+                </SelectItem>
+              ))}
+            </SelectContent>
+          </Select>
+          <Input
+            type="url"
+            aria-label="URL"
+            name="url"
+            placeholder="Enter URL here..."
+            autoComplete="off"
+            spellCheck={false}
+            maxLength={2083}
+            className="mx-3 w-full"
+            defaultValue={spec.url || ""}
+            onChange={handleUrlChange}
+            required
+          />
+          <Button type="submit" className="px-10">
+            Run
+          </Button>
+        </div>
+
+        <div className="mt-5 h-3/4">
+          <BodyEditor
+            name="body"
+            defaultValue={spec.body}
+            onChange={handleBodyChange}
+          />
+        </div>
       </form>
-      <div className="mt-5">
+
+      <div className="mt-5 overflow-y-auto">
         {runtime.step === "running" && <RuntimeProgressBar />}
 
         {(runtime.step === "success" || runtime.step == "unsuccess") && (