Continuum — One Dashboard. Everything You Track.

What is Continuum?

Continuum is a self-hosted, privacy-first dashboard that replaces a pile of single-purpose tracking apps — budget spreadsheet, Letterboxd, Goodreads, subscription reminders — with one place to manage expenses, investment portfolios, media watchlists, book libraries, and recurring subscriptions.
It started as a personal API I fed into a Custom GPT so I could log expenses over chat instead of paying for another app. A friend wanted it too, so instead of handing over my personal API collection I built an actual dashboard around it. It's designed to natively integrate with AI assistants through a standardized OpenAPI schema.

Technical Details

Framework: Next.js 16 (App Router, Turbopack) + React 19 + TypeScript
Styling: Tailwind CSS
Database & Auth: Firebase (Google Sign-In + Firestore REST API)

Features

• Expense ledger with categorized transactions, location-specific currencies, and custom financial-period filtering.
• Investment portfolio tracking across equities, crypto, mutual funds/SIPs, gold, cash, and fixed deposits — manual entry or live valuation.
• Unified media watchlist with bidirectional AniList and Trakt sync, Letterboxd CSV imports, and metadata enrichment via OMDb and TVMaze.
• Book library backed by the OpenLibrary API with reading-progress tracking.
• Subscription tracker that normalizes monthly and annual costs into a true effective monthly spend.
• Auto-saving scratchpad for quick, persistent notes.
• Built-in OpenAPI 3.1 schema for Custom GPT Actions, Gemini Gems, or Claude Projects — add expenses, log media, or update your portfolio in plain English.
• AES-256-GCM encryption on sensitive fields, with no admin service account — every request is authenticated with the caller's own Firebase ID token.

Run Using Node.js

Clone the Repository

git clone https://github.com/fal3n-4ngel/Continuum-Home.git
cd Continuum-Home

Install Dependencies

npm install

Configure Firebase

1. Create a project in the Firebase Console.
2. Enable Google Sign-in under Authentication → Sign-in method.
3. Provision a Firestore Database.
4. Project Settings → General → Add Web App to generate the config snippet.
5. Deploy the security rules that isolate each user's data:

npm install -g firebase-tools
firebase login
firebase use --add
firebase deploy --only firestore:rules

Set Environment Variables

cp .env.example .env.local

Set FIREBASE_CONFIG as a minified JSON string and pick an encryption key in .env.local:

FIREBASE_CONFIG={"apiKey":"...","authDomain":"...","projectId":"..."}
ENCRYPTION_KEY="your-custom-super-secret-key-phrase"

Optional keys for Trakt, AniList, and TMDb can also go here — see .env.example.

Tip

Bring-your-own-config mode: server-wide env vars for third-party APIs are optional. Users can instead supply their own credentials per-request via HTTP headers (X-Firebase-Config, X-Trakt-Client-Id, etc.) — see lib/credentials.ts.

Run the Development Server

npm run dev

Run the Production Server

npm run build
npm run start

Access the Website

Open your browser and navigate to

http://{ip}:3000

🔒 Security Model

• No admin service account. The backend never holds elevated database credentials — every write is routed through the Firestore REST API, authenticated with the caller's own Firebase ID token.
• AES-256-GCM encryption on sensitive fields (titles, categories, amounts, notes) before they hit Firestore.
• Per-user isolation enforced by ownership checks in firestore.rules.
• Hardened API routes — payloads are validated at the boundary, and upstream proxy routes are strictly allowlisted against SSRF.

🤖 Talk to Continuum via ChatGPT

Continuum exposes an OpenAPI schema (/api/openapi.json) so you can add expenses, log media, or check your portfolio from a chat window instead of the UI.

Official Public Custom GPT

Open the Continuum Assistant. Authorization runs through standard OAuth 2.0 on your first prompt.

Configure a Custom GPT for your own self-hosted instance

1. In ChatGPT: Explore GPTs → Create → Configure → Actions.
2. Import Schema: point it at https://your-domain.com/api/openapi.json.
3. Configure Authentication → OAuth:
   • Client ID & Secret: any dummy strings (e.g. client / secret).
   • Authorization URL: https://your-domain.com/api/oauth/authorize
   • Token URL: https://your-domain.com/api/oauth/token
   • Token Exchange Method: Default (POST request).
4. Instructions: paste the contents of CUSTOM_GPT_INSTRUCTIONS.md.
5. Save and publish.

Troubleshooting

1. Portfolio / expense data won't decrypt, or looks garbled

• Symptoms
  • Fields render as blank or as raw ciphertext
  • Data written before now still won't read back correctly
• Troubleshooting Steps

  # ENCRYPTION_KEY must stay identical for the lifetime of your data —
  # changing it makes everything encrypted under the old key unreadable.
  # Confirm .env.local matches what was used when the data was written.

2. Google Sign-in fails or Firestore requests get rejected

• Symptoms
  • Login redirects back to the login screen
  • API routes return 401/403
• Troubleshooting Steps

  # Confirm Google Sign-in is enabled in Firebase Console → Authentication
  # Confirm `firebase deploy --only firestore:rules` was run against the right project
  # Confirm FIREBASE_CONFIG in .env.local matches the same Firebase project

3. Daily cron emails / Custom GPT Actions aren't firing

• Symptoms
  • No daily portfolio/expense/subscription emails
  • Custom GPT Action calls fail silently
• Troubleshooting Steps

  # Confirm CRON_SECRET and RESEND_API_KEY are set in your deployment env
  # Confirm the GitHub Actions cron workflows have APP_URL and CRON_SECRET as repo secrets
  # Check /api/cron/health for a live status check

Contributors

Adithya Krishnan

License

This project is open-source and available under the MIT License.

Interested in improving Continuum? I welcome contributions! See CONTRIBUTING.md for issue/branch conventions and CI requirements, or just open an issue, submit a PR, or share ideas on GitHub. Together, we can make this project even better.

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📝 Authors' Note

Well, it's been a while since I worked on any public projects—mostly coz I rarely get time after work, and even when I do, it's usually personal APIs or portfolio updates.

I already had a system to track my expenses and movies via my personal API, which I enhanced when ChatGPT released Custom GPTs so I could add stuff directly via chat (use AI without paying for an API). Instead of putting AI inside my API, I put my API inside AI (sounded cool in my head).

Anyway, a friend saw it and wanted it too, so rather than handing over my personal API collection, I decided to build a proper dashboard instead. And here we are!

Anyways, hosting a custom gpt is kinda costly so not sure how long I might keep that up, feel free to host your own one or sponsor me via the button below :)

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