Next.js AI Chat Web App Development
Budget: $30 – $250 USD
I’ve already built most of a Next.js-based AI chat web app using Firebase for authentication and Firestore as the database.
The interface and layout are complete — I just need someone to ensure that the core user logic and payment flow are working properly end-to-end.
The app is a simple AI chat tool that uses a credit-based system, where users spend credits to send messages.
There’s no free tier — users must purchase credits or subscribe before using the app.
⸻
What You’ll Do
• Integrate Paddle payments via their API (not checkout links) for subscriptions and credit purchases
• Implement credit tracking and usage limits (each message deducts from the user’s balance)
• Ensure all user flows work properly, including:
• Creating a new chat
• Retrieving and displaying chat history
• Saving chats persistently in Firestore
• Handling cases where a user’s credits run out (block usage + show upgrade prompt)
• Debug and finalize the end-to-end flow (auth → payment → chat → persistence)
• Confirm the app is fully functional and stable for production deployment
⸻
Tech Stack
• Next.js (App Router)
• Firebase / Firestore
• Paddle API (for subscriptions and credits)
• React + shadcn/ui components
• AI API endpoint for chat responses (already integrated)
⸻
Deliverables
• Working Paddle integration with API + webhooks
• Fully functional credit system (deduct on message, block on zero balance) inclusive of full intergration of the ai.
• Chat persistence (save + reload user conversations)
• Verified user flow from sign-up to payment to chat usage
• General QA to ensure smooth, bug-free operation
⸻
Confidentiality
You’ll sign a brief NDA before getting repository access.
You don’t need to know the broader business concept — the task focuses purely on functionality and integrations.
⸻
Ideal Candidate
• Strong knowledge of Next.js (App Router) and Firebase
• Experience integrating payment systems like Paddle, Stripe, or Lemon Squeezy
• Familiarity with credit or usage-based SaaS logic
• Solid debugging, async handling, and Firestore data structuring skills
⸻
Budget
Open to hourly or fixed — depending on the scope after initial review.
⸻
Summary
This is a straightforward role:
You’re finalizing a basic AI chat app with a credit system — making sure users can sign up, pay, chat, and have their credits, chats, and state persist correctly.
No design work is needed — just solid functionality.
The interface and layout are complete — I just need someone to ensure that the core user logic and payment flow are working properly end-to-end.
The app is a simple AI chat tool that uses a credit-based system, where users spend credits to send messages.
There’s no free tier — users must purchase credits or subscribe before using the app.
⸻
What You’ll Do
• Integrate Paddle payments via their API (not checkout links) for subscriptions and credit purchases
• Implement credit tracking and usage limits (each message deducts from the user’s balance)
• Ensure all user flows work properly, including:
• Creating a new chat
• Retrieving and displaying chat history
• Saving chats persistently in Firestore
• Handling cases where a user’s credits run out (block usage + show upgrade prompt)
• Debug and finalize the end-to-end flow (auth → payment → chat → persistence)
• Confirm the app is fully functional and stable for production deployment
⸻
Tech Stack
• Next.js (App Router)
• Firebase / Firestore
• Paddle API (for subscriptions and credits)
• React + shadcn/ui components
• AI API endpoint for chat responses (already integrated)
⸻
Deliverables
• Working Paddle integration with API + webhooks
• Fully functional credit system (deduct on message, block on zero balance) inclusive of full intergration of the ai.
• Chat persistence (save + reload user conversations)
• Verified user flow from sign-up to payment to chat usage
• General QA to ensure smooth, bug-free operation
⸻
Confidentiality
You’ll sign a brief NDA before getting repository access.
You don’t need to know the broader business concept — the task focuses purely on functionality and integrations.
⸻
Ideal Candidate
• Strong knowledge of Next.js (App Router) and Firebase
• Experience integrating payment systems like Paddle, Stripe, or Lemon Squeezy
• Familiarity with credit or usage-based SaaS logic
• Solid debugging, async handling, and Firestore data structuring skills
⸻
Budget
Open to hourly or fixed — depending on the scope after initial review.
⸻
Summary
This is a straightforward role:
You’re finalizing a basic AI chat app with a credit system — making sure users can sign up, pay, chat, and have their credits, chats, and state persist correctly.
No design work is needed — just solid functionality.