Posted on Sep 18

🚀 How I Built an AI SaaS Product Description Generator with Next.js + OpenAI

#nextjs #chatgpt #ai

If you’ve ever launched a SaaS project, you know this pain: writing the product description is harder than building the actual product.

You end up listing features nobody cares about.
You try to sound clever but just sound like every other startup.
Or worse—you freeze at a blank page and lose momentum.

I wanted a repeatable way to write sharp, benefit-driven copy that converts. Something better than tweaking ChatGPT prompts endlessly.

So I built the SaaS Product Description Generator.

✨ What It Does

Input: Product name, target customer, and the problem it solves.
Output: 5 short, benefit-driven descriptions (perfect for landing pages, hero sections, or social posts) + 1 longer description (great for directories, docs, and about pages).
Consistency: Unlike ChatGPT “hit or miss” answers, this tool enforces a structured prompt and JSON format, so the results are repeatable every time.

✅ Why It Matters

This isn’t just copywriting—it’s positioning.

When your product description:

Starts with customer pain → you instantly connect.
Highlights benefits over features → people see why it matters.
Uses clear, persuasive language → you get conversions, not confusion.

And if you’re an indie dev, you don’t have time to overthink copy. You just need something solid to ship now.

🛠️ How It’s Built

I kept it brutally simple:

A Next.js API endpoint that calls OpenAI with a structured prompt.
A frontend form with three inputs and one button.
Instant AI-generated JSON → displayed as product descriptions.

No dashboards. No fluff. Just type → generate → copy → ship.

🚀 Try It Out

👉 SaaS Product Description Generator

It’s free and built for indie hackers, SaaS founders, and devs who just want to get their product out the door without getting stuck on copywriting.

🧩 Setting Up the Backend API

The API endpoint needed to:

Accept structured input (productName, targetCustomer, problemSolved).
Pass a strong system prompt to OpenAI that enforces benefit-driven copywriting rules.
Always return structured JSON (5 short descriptions + 1 long description).

Example: Next.js Route Handler with OpenAI

import { NextRequest, NextResponse } from 'next/server';
import { generateText } from 'ai';
import { openai } from '@ai-sdk/openai';

export const runtime = 'nodejs';

export async function POST(req: NextRequest) {
  try {
    const { productName, targetCustomer, problemSolved } = await req.json();

    if (!productName?.trim() || !targetCustomer?.trim() || !problemSolved?.trim()) {
      return NextResponse.json({ 
        error: 'Product name, target customer, and problem solved are all required' 
      }, { status: 400 });
    }

    const systemPrompt = `You are an expert SaaS copywriter...`;  
    const prompt = `Product Name: ${productName}
Target Customer: ${targetCustomer}
Problem Solved: ${problemSolved}`;

    const result = await generateText({
      model: openai('gpt-4o-mini'),
      temperature: 0.7,
      system: systemPrompt,
      prompt,
    });

    const descriptions = JSON.parse(result.text);

    if (!descriptions.shortDescriptions || descriptions.shortDescriptions.length !== 5) {
      return NextResponse.json({ error: 'Invalid response format' }, { status: 500 });
    }

    return NextResponse.json(descriptions, { status: 200 });
  } catch {
    return NextResponse.json({ error: 'Internal server error' }, { status: 500 });
  }
}

And here is the full system prompt:

You are an expert copywriter specializing in SaaS product descriptions for indie founders and startups.

Your job is to transform feature-focused descriptions into benefit-driven copy that converts. Focus on:
- Customer pain points first, then solutions
- Clear benefits over features
- Persuasive, conversion-focused language
- Multiple positioning angles
- Ready-to-use marketing copy

You will receive:
- Product Name
- Target Customer
- Problem Solved

Generate ONLY a valid JSON object (no other text) with this exact structure:

{
  "shortDescriptions": [
    "Description 1 (1-2 sentences, landing page style)",
    "Description 2 (1-2 sentences, different angle)",
    "Description 3 (1-2 sentences, different angle)",
    "Description 4 (1-2 sentences, different angle)",
    "Description 5 (1-2 sentences, different angle)"
  ],
  "longDescription": "One paragraph description suitable for directories, documentation, or detailed product pages. Should be comprehensive while still benefit-focused."
}

Requirements for each description:
- Start with customer pain point or desired outcome
- Emphasize benefits and value, not features
- Use clear, persuasive language
- Vary the positioning angle (speed, simplicity, results, etc.)
- Make them conversion-focused
- Keep short descriptions to 1-2 sentences max
- Make the long description 3-5 sentences

Examples of benefit-driven language:
- "Stop wasting hours on..." instead of "We automate..."
- "Get results in minutes" instead of "Fast processing"
- "Never lose customers again" instead of "Customer retention features"
- "Turn visitors into customers" instead of "Conversion optimization tools"`;

This guarantees the output is always consistent JSON—not rambling AI text.

🎨 Building the Frontend with React (Next.js Client Component)

The frontend is a single-page form:

Input fields for product name, target customer, and problem solved.
Submit button that calls the API.
Results area that shows five short product descriptions + one long description.

Example: React Client Component

"use client";

import { useState } from "react";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Textarea } from "@/components/ui/textarea";

interface DescriptionResult {
  shortDescriptions: string[];
  longDescription: string;
}

export function SaasDescriptionGeneratorClient() {
  const [productName, setProductName] = useState("");
  const [targetCustomer, setTargetCustomer] = useState("");
  const [problemSolved, setProblemSolved] = useState("");
  const [result, setResult] = useState<DescriptionResult | null>(null);

  const handleGenerate = async () => {
    const response = await fetch("/api/saas-description-generator", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ productName, targetCustomer, problemSolved }),
    });
    const data = await response.json();
    setResult(data);
  };

  return (
    <div>
      <Input value={productName} onChange={(e) => setProductName(e.target.value)} placeholder="Product Name" />
      <Input value={targetCustomer} onChange={(e) => setTargetCustomer(e.target.value)} placeholder="Target Customer" />
      <Textarea value={problemSolved} onChange={(e) => setProblemSolved(e.target.value)} placeholder="Problem Solved" />
      <Button onClick={handleGenerate}>Generate Descriptions</Button>

      {result && (
        <>
          {result.shortDescriptions.map((desc, i) => (
            <p key={i}>{desc}</p>
          ))}
          <h4>Long Description:</h4>
          <p>{result.longDescription}</p>
        </>
      )}
    </div>
  );
}

🔑 Why This Approach Works

Repeatable AI results → By forcing JSON, you avoid inconsistent responses.
Benefit-driven copy → Each description starts with a pain point and ends with a benefit.
Super simple UX → Just one form, one button, instant product descriptions.

This is perfect for indie hackers and SaaS developers who want to:

Improve landing page copy.
Prepare for a Product Hunt launch.
Write sharper descriptions for directories like Betalist, PH, or IndieHackers.

🚀 Try the Live AI Product Description Generator