---
title: "Persist PDF ink signatures across instances | Nutrient"
canonical_url: "https://www.nutrient.io/guides/web/knowledge-base/persist-ink-signatures-across-instances/"
md_url: "https://www.nutrient.io/guides/web/knowledge-base/persist-ink-signatures-across-instances.md"
last_updated: "2026-05-18T15:18:35.785Z"
description: "Ink signatures aren’t automatically persisted in memory by Nutrient Web SDK. This is something that needs to be implemented."
---

Ink signatures aren’t automatically persisted in memory by Nutrient Web SDK. This is something that needs to be implemented.

One possibility is to store the ink signatures on the browser local storage and populate the list of ink signatures when an instance of Nutrient is loaded. To retrieve the ink signatures, you can use [`NutrientViewer.Instance#getInkSignatures`](https://www.nutrient.io/api/web/NutrientViewer.Instance.html#getInkSignatures) and populate the list when it’s loading with the [`NutrientViewer.Configuration#populateInkSignatures`](https://www.nutrient.io/api/web/NutrientViewer.Configuration.html#populateInkSignatures) property:

```js

const serializedSignatures = localStorage.getItem(
  "signaturesSerialized"
);
const configuration = defaultConfiguration; // Replace this with your configuration options.

if (serializedSignatures) {
  const parsed = JSON.parse(serializedSignatures);
  const list = NutrientViewer.Immutable.List(
    parsed.map(NutrientViewer.Annotations.fromSerializableObject)
  );
  configuration.populateInkSignatures = () => list;
}

NutrientViewer.load(configuration).then((instance) => {
  console.log("PSPDFKit for Web successfully loaded!!", instance);

  // We listen to any change creation/update/deletion of ink signatures.
  instance.addEventListener("inkSignatures.change", async () => {
    const list = await instance.getInkSignatures();
    const serialized = list.map(NutrientViewer.Annotations.toSerializableObject).toJS();
    localStorage.setItem(
      "signaturesSerialized",
      JSON.stringify(serialized)
    );
  });
  return instance;
});

```

You can enhance this further by, for instance, sending the serialized list of ink signatures to a server instead of keeping it persisted in the client’s storage. Refer to our guide on [storing signatures](https://www.nutrient.io/guides/web/signatures/signature-storage.md) to learn more.

This has been tested with Nutrient Web SDK 2020.2.5.
---

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