docs: add Nango OAuth integration guide (#3262)

Adds a guide showing how to use Nango to make authenticated API calls
inside a Trigger.dev task, using GitHub + Claude as a concrete example.

Author: isshaddad

docs/docs.json

@@ -369,6 +369,7 @@
               "guides/ai-agents/claude-code-trigger",
               "guides/frameworks/drizzle",
               "guides/frameworks/prisma",
+              "guides/frameworks/nango",
               "guides/frameworks/sequin",
               {
                 "group": "Supabase",

docs/guides/frameworks/nango.mdx

@@ -0,0 +1,287 @@
+---
+title: "Nango OAuth with Trigger.dev"
+sidebarTitle: "Nango OAuth guide"
+description: "Use Nango to authenticate API calls inside a Trigger.dev task, no token management required."
+icon: "key"
+---
+
+[Nango](https://www.nango.dev/) handles OAuth for 250+ APIs, storing and automatically refreshing access tokens on your behalf. This makes it a natural fit for Trigger.dev tasks that need to call third-party APIs on behalf of your users.
+
+In this guide you'll build a task that:
+
+1. Receives a Nango `connectionId` from your frontend
+2. Fetches a fresh GitHub access token from Nango inside the task
+3. Calls the GitHub API to retrieve the user's open pull requests
+4. Uses Claude to summarize what's being worked on
+
+This pattern works for any API Nango supports. Swap GitHub for HubSpot, Slack, Notion, or any other provider.
+
+## Prerequisites
+
+- A Next.js project with [Trigger.dev installed](/guides/frameworks/nextjs)
+- A [Nango](https://app.nango.dev/) account
+- An [Anthropic](https://console.anthropic.com/) API key
+
+## How it works
+
+```mermaid
+sequenceDiagram
+  participant User
+  participant Frontend
+  participant API as Next.js API
+  participant TD as Trigger.dev task
+  participant Nango
+  participant GH as GitHub API
+  participant Claude
+
+  User->>Frontend: Clicks "Analyze my PRs"
+  Frontend->>API: POST /api/nango-session
+  API->>Nango: POST /connect/sessions (secret key)
+  Nango-->>API: session token (30 min TTL)
+  API-->>Frontend: session token
+  Frontend->>Nango: OAuth connect (frontend SDK + session token)
+  Nango-->>Frontend: connectionId
+  Frontend->>API: POST /api/analyze-prs { connectionId, repo }
+  API->>TD: tasks.trigger(...)
+  TD->>Nango: getConnection(connectionId)
+  Nango-->>TD: access_token
+  TD->>GH: GET /repos/:repo/pulls
+  GH-->>TD: open pull requests
+  TD->>Claude: Summarize PRs
+  Claude-->>TD: Summary
+```
+
+## Step 1: Connect GitHub in Nango
+
+<Steps titleSize="h3">
+  <Step title="Create a GitHub integration in Nango">
+    1. In your [Nango dashboard](https://app.nango.dev/), go to **Integrations** and click **Set up new integration**.
+    2. Search for **GitHub** and select GitHub (User OAuth).
+    3. Create and add a test connection
+  </Step>
+  <Step title="Add the Nango frontend SDK">
+    Install the Nango frontend SDK in your Next.js project:
+
+    ```bash
+    npm install @nangohq/frontend
+    ```
+
+    The frontend SDK requires a short-lived **connect session token** issued by your backend. Add an API route that creates the session:
+
+    ```ts app/api/nango-session/route.ts
+    import { NextResponse } from "next/server";
+
+    export async function POST(req: Request) {
+      const { userId } = await req.json();
+
+      if (!userId || typeof userId !== "string") {
+        return NextResponse.json({ error: "Missing or invalid userId" }, { status: 400 });
+      }
+
+      const response = await fetch("https://api.nango.dev/connect/sessions", {
+        method: "POST",
+        headers: {
+          Authorization: `Bearer ${process.env.NANGO_SECRET_KEY}`,
+          "Content-Type": "application/json",
+        },
+        body: JSON.stringify({
+          end_user: { id: userId },
+        }),
+      });
+
+      if (!response.ok) {
+        const text = await response.text();
+        console.error("Nango error:", response.status, text);
+        return NextResponse.json({ error: text }, { status: response.status });
+      }
+
+      const { data } = await response.json();
+      return NextResponse.json({ token: data.token });
+    }
+    ```
+
+    Then add a connect button to your UI that fetches the token and opens the Nango OAuth flow:
+
+    ```tsx app/page.tsx
+    "use client";
+
+    import Nango from "@nangohq/frontend";
+
+    export default function Page() {
+      async function connectGitHub() {
+        // Get a short-lived session token from your backend
+        const sessionRes = await fetch("/api/nango-session", {
+          method: "POST",
+          headers: { "Content-Type": "application/json" },
+          body: JSON.stringify({ userId: "user_123" }), // replace with your actual user ID
+        });
+        const { token } = await sessionRes.json();
+
+        const nango = new Nango({ connectSessionToken: token });
+        // Use the exact integration slug from your Nango dashboard
+        const result = await nango.auth("<your-integration-slug>");
+
+        // result.connectionId is what you pass to your task
+        await fetch("/api/analyze-prs", {
+          method: "POST",
+          headers: { "Content-Type": "application/json" },
+          body: JSON.stringify({
+            connectionId: result.connectionId,
+            repo: "triggerdotdev/trigger.dev",
+          }),
+        });
+      }
+
+      return <button onClick={connectGitHub}>Analyze my PRs</button>;
+    }
+    ```
+
+  </Step>
+</Steps>
+
+## Step 2: Create the Trigger.dev task
+
+Install the required packages:
+
+```bash
+npm install @nangohq/node @anthropic-ai/sdk
+```
+
+Create the task:
+
+<CodeGroup>
+
+```ts trigger/analyze-prs.ts
+import { task } from "@trigger.dev/sdk";
+import { Nango } from "@nangohq/node";
+import Anthropic from "@anthropic-ai/sdk";
+
+const nango = new Nango({ secretKey: process.env.NANGO_SECRET_KEY! });
+const anthropic = new Anthropic();
+
+export const analyzePRs = task({
+  id: "analyze-prs",
+  run: async (payload: { connectionId: string; repo: string }) => {
+    const { connectionId, repo } = payload;
+
+    // Fetch a fresh access token from Nango. It handles refresh automatically.
+    // Use the exact integration slug from your Nango dashboard, e.g. "github-getting-started"
+    const connection = await nango.getConnection("<your-integration-slug>", connectionId);
+
+    if (connection.credentials.type !== "OAUTH2") {
+      throw new Error(`Unexpected credentials type: ${connection.credentials.type}`);
+    }
+
+    const accessToken = connection.credentials.access_token;
+    // Call the GitHub API on behalf of the user
+    const response = await fetch(
+      `https://api.github.com/repos/${repo}/pulls?state=open&per_page=20`,
+      {
+        headers: {
+          Authorization: `Bearer ${accessToken}`,
+          Accept: "application/vnd.github.v3+json",
+        },
+      }
+    );
+
+    if (!response.ok) {
+      throw new Error(`GitHub API error: ${response.status} ${response.statusText}`);
+    }
+
+    const prs = await response.json();
+
+    if (prs.length === 0) {
+      return { summary: "No open pull requests found.", prCount: 0 };
+    }
+
+    // Use Claude to summarize what's being worked on
+    const prList = prs
+      .map(
+        (pr: { number: number; title: string; user: { login: string }; body: string | null }) =>
+          `#${pr.number} by @${pr.user.login}: ${pr.title}\n${pr.body?.slice(0, 200) ?? ""}`
+      )
+      .join("\n\n");
+
+    const message = await anthropic.messages.create({
+      model: "claude-opus-4-6",
+      max_tokens: 1024,
+      messages: [
+        {
+          role: "user",
+          content: `Here are the open pull requests for ${repo}. Give a concise summary of what's being worked on, grouped by theme where possible.\n\n${prList}`,
+        },
+      ],
+    });
+
+    const summary = message.content[0].type === "text" ? message.content[0].text : "";
+
+    return { summary, prCount: prs.length };
+  },
+});
+```
+
+</CodeGroup>
+
+## Step 3: Create the API route
+
+Add a route handler that receives the `connectionId` from your frontend and triggers the task:
+
+```ts app/api/analyze-prs/route.ts
+import { analyzePRs } from "@/trigger/analyze-prs";
+import { NextResponse } from "next/server";
+
+export async function POST(req: Request) {
+  const { connectionId, repo } = await req.json();
+
+  if (!connectionId || !repo) {
+    return NextResponse.json({ error: "Missing connectionId or repo" }, { status: 400 });
+  }
+
+  const handle = await analyzePRs.trigger({ connectionId, repo });
+
+  return NextResponse.json(handle);
+}
+```
+
+## Step 4: Set environment variables
+
+Add the following to your `.env.local` file:
+
+```bash
+NANGO_SECRET_KEY=      # From Nango dashboard → Environment → Secret key
+TRIGGER_SECRET_KEY=    # From Trigger.dev dashboard → API keys
+ANTHROPIC_API_KEY=     # From Anthropic console
+```
+
+Add `NANGO_SECRET_KEY` and `ANTHROPIC_API_KEY` as [environment variables](/deploy-environment-variables) in your Trigger.dev project too. These are used inside the task at runtime.
+
+## Test it
+
+<Steps titleSize="h3">
+  <Step title="Start your dev servers">
+
+    ```bash
+    npm run dev
+    npx trigger.dev@latest dev
+    ```
+
+  </Step>
+  <Step title="Connect GitHub and trigger the task">
+    Open your app, click **Analyze my PRs**, and complete the GitHub OAuth flow. The task will be triggered automatically.
+  </Step>
+  <Step title="Watch the run in Trigger.dev">
+    Open your [Trigger.dev dashboard](https://cloud.trigger.dev/) and navigate to **Runs** to see the task execute. You'll see the PR count and Claude's summary in the output.
+  </Step>
+</Steps>
+
+<Check>
+  Your task is now fetching a fresh GitHub token from Nango, calling the GitHub API on behalf of the
+  user, and using Claude to summarize their open PRs. No token storage or refresh logic required.
+</Check>
+
+## Next steps
+
+- **Reuse the `connectionId`**: Once a user has connected, store their `connectionId` and pass it in future task payloads. No need to re-authenticate.
+- **Add retries**: If the GitHub API returns a transient error, Trigger.dev [retries](/errors-retrying) will handle it automatically.
+- **Switch providers**: The same pattern works for any Nango-supported API. Change `"github"` to `"hubspot"`, `"slack"`, `"notion"`, or any other provider.
+- **Stream the analysis**: Use [Trigger.dev Realtime](/realtime/overview) to stream Claude's response back to your frontend as it's generated.