---
lang: en
title: 'API docs: authentication-jwt.jwtservice._constructor_'
keywords: LoopBack 4.0, LoopBack 4, Node.js, TypeScript, OpenAPI
sidebar: lb4_sidebar
editurl: https://github.com/loopbackio/loopback-next/tree/master/extensions/authentication-jwt
permalink: /doc/en/lb4/apidocs.authentication-jwt.jwtservice._constructor_.html
---

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[Home](./index.md) &gt; [@loopback/authentication-jwt](./authentication-jwt.md) &gt; [JWTService](./authentication-jwt.jwtservice.md) &gt; [(constructor)](./authentication-jwt.jwtservice._constructor_.md)

## JWTService.(constructor)

Constructs a new instance of the `JWTService` class

**Signature:**

```typescript
constructor(jwtSecret: string, jwtExpiresIn: string);
```

## Parameters

<table><thead><tr><th>

Parameter


</th><th>

Type


</th><th>

Description


</th></tr></thead>
<tbody><tr><td markdown="1">

jwtSecret


</td><td markdown="1">

string


</td><td markdown="1">


</td></tr>
<tr><td markdown="1">

jwtExpiresIn


</td><td markdown="1">

string


</td><td markdown="1">


</td></tr>
</tbody></table>