diff --git a/README.md b/README.md
index a86a700..bef6589 100644
--- a/README.md
+++ b/README.md
@@ -284,10 +284,10 @@ import { Trans } from "astro-i18next/components";
 
 #### Trans Props
 
-| Prop name | Type (default)      | Description                                                                                                                                            |
-| --------- | ------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ |
-| i18nKey   | string (undefined)  | Internationalization key to interpolate to. Can contain the namespace by prepending it in the form 'ns:key' (depending on i18next.options.nsSeparator) |
-| ns        | ?string (undefined) | Namespace to use. May also be embedded in i18nKey but not recommended when used in combination with natural language keys.                             |
+| Prop name | Type (default)      | Description                                                                                                                                                                                                                            |
+| --------- | ------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| i18nKey   | ?string (undefined) | Internationalization key to interpolate to. Can contain the namespace by prepending it in the form 'ns:key' (depending on i18next.options.nsSeparator). If omitted, a key is automatically generated using the content of the element. |
+| ns        | ?string (undefined) | Namespace to use. May also be embedded in i18nKey but not recommended when used in combination with natural language keys.                                                                                                             |
 
 ### LanguageSelector component
 
diff --git a/src/__tests__/utils.test.ts b/src/__tests__/utils.test.ts
index c371f89..c4a68e3 100644
--- a/src/__tests__/utils.test.ts
+++ b/src/__tests__/utils.test.ts
@@ -1,5 +1,6 @@
 import {
   interpolate,
+  createReferenceStringFromHTML,
   localizePath,
   moveBaseLanguageToFirstIndex,
   localizeUrl,
@@ -21,6 +22,7 @@ i18next.init({
       translation: {
         hello: "Hello!",
         interpolationKey: "This is a <0>super cool</0> sentence!",
+        interpolationKeySelfClosing: "This has an image <0> here",
         interpolationKeyNoHTML:
           "This is a reference string without any HTML tags!",
       },
@@ -29,6 +31,7 @@ i18next.init({
       translation: {
         hello: "Bonjour !",
         interpolationKey: "Ceci est une phrase <0>super cool</0> !",
+        interpolationKeySelfClosing: "Ceci a une image <0> ici",
         interpolationKeyNoHTML:
           "Ceci est une chaîne de caractères de référence, sans aucune balise HTML !",
       },
@@ -75,12 +78,28 @@ describe("interpolate(...)", () => {
     );
   });
 
+  it("interpolates localized string with self-closing HTML tags", () => {
+    i18next.changeLanguage("fr");
+    const referenceString = 'This has an image <img src="./img.png"> here';
+    const interpolatedStringFR = 'Ceci a une image <img src="./img.png"> ici';
+
+    expect(interpolate("interpolationKeySelfClosing", referenceString)).toBe(
+      interpolatedStringFR
+    );
+
+    i18next.changeLanguage("en");
+    expect(interpolate("interpolationKeySelfClosing", referenceString)).toBe(
+      'This has an image <img src="./img.png"> here'
+    );
+  });
+
   it("with an i18nKey that is undefined", () => {
     expect(interpolate("missingKey", referenceString)).toBe(referenceString);
     expect(console.warn).toHaveBeenCalled();
   });
 
   it("with no HTML tags in default slot", () => {
+    i18next.changeLanguage("en");
     expect(
       interpolate(
         "interpolationKeyNoHTML",
@@ -91,6 +110,7 @@ describe("interpolate(...)", () => {
   });
 
   it("with malformed HTML tags in default slot", () => {
+    i18next.changeLanguage("en");
     expect(
       interpolate(
         "interpolationKeyNoHTML",
@@ -101,6 +121,90 @@ describe("interpolate(...)", () => {
   });
 });
 
+describe("createReferenceStringFromHTML(...)", () => {
+  it("replaces HTML elements", () => {
+    expect(createReferenceStringFromHTML("Single <h1>element</h1>")).toBe(
+      "Single <0>element</0>"
+    );
+    expect(
+      createReferenceStringFromHTML(
+        'Multiple <div class="wrapper" id="head"><h1>Elements</h1><p>Nested and with attributes</p></div>'
+      )
+    ).toBe("Multiple <0><1>Elements</1><2>Nested and with attributes</2></0>");
+
+    expect(
+      createReferenceStringFromHTML(
+        '<p>Self <img src="./img.png"> closing tags</p>'
+      )
+    ).toBe("<0>Self <1> closing tags</0>");
+  });
+
+  it("ignores allowed elements with no attributes", () => {
+    expect(
+      createReferenceStringFromHTML("<p>Text with <em>emphasis</em></p>")
+    ).toEqual("<0>Text with <em>emphasis</em></0>");
+
+    expect(
+      createReferenceStringFromHTML(
+        '<p>Text with <em class="test">emphasis</em></p>'
+      )
+    ).toEqual("<0>Text with <1>emphasis</1></0>");
+
+    expect(
+      createReferenceStringFromHTML("<em>Text with <div>div</div></em>")
+    ).toEqual("<em>Text with <1>div</1></em>");
+  });
+
+  it("warns when contains separator strings", () => {
+    const keySeparator = i18next.options.keySeparator;
+
+    expect(
+      createReferenceStringFromHTML(
+        `<p>Text with <em>emphasis</em>${keySeparator}</p>`
+      )
+    ).toEqual(`<0>Text with <em>emphasis</em>${keySeparator}</0>`);
+
+    expect(console.warn).toHaveBeenCalled();
+  });
+
+  it("collapses extra whitespace", () => {
+    expect(
+      createReferenceStringFromHTML("Single  \n    \t    <h1>element</h1>")
+    ).toBe("Single <0>element</0>");
+    expect(
+      createReferenceStringFromHTML("   Trims <h1>outer</h1> text     ")
+    ).toBe("Trims <0>outer</0> text");
+  });
+
+  it("does not cause duplicate elements with attributes to be collapsed", () => {
+    expect(
+      createReferenceStringFromHTML(
+        `<span><span class="one">one</span><span class="two">two</span></span>`
+      )
+    ).toBe("<0><1>one</0><2>two</0></0>");
+  });
+});
+
+describe("interpolate(...) and createReferenceStringFromHTML(...)", () => {
+  it("methods undo each other", () => {
+    const html =
+      '<p class="test1" id="test2"><strong>The</strong> text with <img src="./img.png"> image <em>reconstructs</em> properly</p>';
+    const frHtml =
+      '<p class="test1" id="test2"><strong>Le</strong> texte avec <img src="./img.png"> image <em>se reconstruit</em> correctement</p>';
+    const key = createReferenceStringFromHTML(html);
+    const frKey = createReferenceStringFromHTML(frHtml);
+    i18next.addResources("en", "translation", {
+      [key]: key,
+    });
+    i18next.addResources("fr", "translation", {
+      [key]: frKey,
+    });
+
+    i18next.changeLanguage("fr");
+    expect(interpolate(key, html)).toBe(frHtml);
+  });
+});
+
 describe("localizePath(...)", () => {
   vi.spyOn(console, "warn");
 
diff --git a/src/components/Trans.astro b/src/components/Trans.astro
index 420a012..d446111 100644
--- a/src/components/Trans.astro
+++ b/src/components/Trans.astro
@@ -1,14 +1,21 @@
 ---
-import { interpolate } from "../utils";
+import { interpolate, createReferenceStringFromHTML } from "../utils";
 
 export interface Props {
-  i18nKey: string;
+  i18nKey?: string;
   ns?: string;
 }
 
 const { i18nKey, ns } = Astro.props;
 
 const referenceString = await Astro.slots.render("default");
+
+let key: string;
+if (typeof i18nKey === "string") {
+  key = i18nKey;
+} else {
+  key = createReferenceStringFromHTML(referenceString);
+}
 ---
 
-<Fragment set:html={interpolate(i18nKey, referenceString, ns)} />
+<Fragment set:html={interpolate(key, referenceString, ns)} />
diff --git a/src/utils.ts b/src/utils.ts
index 595d6a8..f557160 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -84,10 +84,12 @@ export const interpolate = (
   let interpolatedString = localizedString;
   for (let index = 0; index < referenceTags.length; index++) {
     const referencedTag = referenceTags[index];
+    // Replace opening tags
     interpolatedString = interpolatedString.replaceAll(
       `<${index}>`,
       `<${referencedTag.name}${referencedTag.attributes}>`
     );
+    // Replace closing tags
     interpolatedString = interpolatedString.replaceAll(
       `</${index}>`,
       `</${referencedTag.name}>`
@@ -97,6 +99,91 @@ export const interpolate = (
   return interpolatedString;
 };
 
+/**
+ * Creates a reference string from an HTML string. The reverse of interpolate(), for use
+ * with <Trans> when not explicitly setting a key
+ */
+export const createReferenceStringFromHTML = (html: string) => {
+  // Allow these tags to carry through to the output
+  const allowedTags = ["strong", "br", "em", "i", "b"];
+
+  let forbiddenStrings: { key: string; str: string }[] = [];
+  if (i18next.options) {
+    forbiddenStrings = [
+      "keySeparator",
+      "nsSeparator",
+      "pluralSeparator",
+      "contextSeparator",
+    ]
+      .map((key) => {
+        const str = i18next.options[key];
+        if (str) {
+          return {
+            key,
+            str: i18next.options[key],
+          };
+        }
+        return undefined;
+      })
+      .filter(function <T>(val: T | undefined): val is T {
+        return typeof val !== "undefined";
+      });
+  }
+
+  const tagsRegex = /<([\w\d]+)([^>]*)>/gi;
+
+  const referenceStringMatches = html.match(tagsRegex);
+
+  if (!referenceStringMatches) {
+    console.warn(
+      "WARNING(astro-i18next): default slot does not include any HTML tag to interpolate! You should use the `t` function directly."
+    );
+    return html;
+  }
+
+  const referenceTags = [];
+  referenceStringMatches.forEach((tagNode) => {
+    const [, name, attributes] = tagsRegex.exec(tagNode);
+    referenceTags.push({ name, attributes });
+
+    // reset regex state
+    tagsRegex.exec("");
+  });
+
+  let sanitizedString = html.replace(/\s+/g, " ").trim();
+  for (let index = 0; index < referenceTags.length; index++) {
+    const referencedTag = referenceTags[index];
+    if (
+      allowedTags.includes(referencedTag.name) &&
+      referencedTag.attributes.trim().length === 0
+    ) {
+      continue;
+    }
+    sanitizedString = sanitizedString.replaceAll(
+      new RegExp(`<${referencedTag.name}[^>]*?\\s*\\/>`, "gi"),
+      `<${index}/>`
+    );
+    sanitizedString = sanitizedString.replaceAll(
+      `<${referencedTag.name}${referencedTag.attributes}>`,
+      `<${index}>`
+    );
+    sanitizedString = sanitizedString.replaceAll(
+      `</${referencedTag.name}>`,
+      `</${index}>`
+    );
+  }
+
+  for (let index = 0; index < forbiddenStrings.length; index++) {
+    const { key, str } = forbiddenStrings[index];
+    if (sanitizedString.includes(str)) {
+      console.warn(
+        `WARNING(astro-i18next): "${str}" was found in a <Trans> translation key, but it is also used as ${key}. Either explicitly set an i18nKey or change the value of ${key}.`
+      );
+    }
+  }
+  return sanitizedString;
+};
+
 /**
  * Injects the given locale to a path
  */