Google Ads Builder Docs

AI-powered ad copy generation for Google Ads. Enter a landing page URL, choose your AI model, and get production-ready RSA headlines, descriptions, sitelinks, callouts, and structured snippets.

🔐 Privacy First This tool runs entirely in your browser. Your API keys are AES-256 encrypted in sessionStorage and never sent to any server other than your chosen AI provider's API.

Quick Start

Three steps to your first batch of ad copy:

Choose Your AI Provider

Pick from Claude (Anthropic), GPT (OpenAI), or Gemini (Google). Each has strengths — Claude tends toward precise character counts, GPT excels at creative variety, Gemini is fast and free-tier friendly.

Sign In + Enter Landing Page URL

Click Sign in with Google to use Buddy credits (25 free credits to start, works across all tools). Or expand "Advanced: Use your own API key" to bring your own. Paste any landing page URL — the AI will analyze it to understand your offer.

Generate & Export

Hit "Generate" and the AI reads your page, extracts value propositions, and creates a full set of ad assets. Copy individual items, copy all, or export as CSV for direct import into Google Ads Editor.

AI Configuration

Recommended: Click "Sign in with Google" to use Buddy credits — one sign-in works across all tools. 25 free credits to start. Or bring your own API key from any provider:

Claude (Anthropic)

choose one

Get your key at console.anthropic.com/settings/keys. Starts with sk-ant-api03-. New accounts get $5 in free credits. Recommended model: Claude Opus 4.6 for best quality.

GPT (OpenAI)

choose one

Get your key at platform.openai.com/api-keys. Starts with sk-proj-. Requires a paid account. Recommended model: GPT-5.2 for best quality.

Gemini (Google)

choose one

Get your key at aistudio.google.com/apikey. Starts with AIzaSy. Generous free tier — great for testing. Recommended model: Gemini 2.0 Flash.

⚠️ Key Security Your key is used for a single direct API call from your browser to the provider. It is never proxied through any server. The key is encrypted in sessionStorage — closing the tab destroys it. We recommend using keys with restricted permissions (rate limits, spend caps) as a best practice.

Generating Ad Copy

The builder sends your landing page URL to the AI with a carefully crafted prompt that instructs it to:

First, analyze your landing page to extract value propositions, CTAs, trust signals (reviews, ratings, awards), competitive positioning, and target audience signals. Then, generate ad copy that maps these insights to Google Ads asset types while strictly respecting character limits.

Optional Context

The "Additional Context" field lets you provide information the AI can't get from the landing page alone. Good things to include:

      example context
Target audience: B2B SaaS buyers, 25-45, VP/Director level
Competitors: Salesforce, HubSpot, Pipedrive
Key differentiator: We're 60% cheaper with same features
Tone: Professional but not corporate. Confident, not aggressive.
Keywords to include: CRM software, sales pipeline, lead management
Avoid: "revolutionary", "game-changing", generic superlatives
Current best-performing headline: "Close 30% More Deals"
    

Asset Types

Asset	Count	Char Limit	Notes
RSA Headlines	15	30 chars	Includes keyword insertion tokens and pin suggestions
RSA Descriptions	4	90 chars	Each designed to work with any headline combination
Sitelink Titles	6	25 chars	Deep links to key pages
Sitelink Descriptions	6 × 2	35 chars	Two description lines per sitelink
Callout Extensions	4	25 chars	Trust signals, benefits, differentiators
Structured Snippets	4	varies	Category header + values

Campaign Types

The builder adapts its output based on your campaign type:

Type	Focus	Example Headlines
Search (RSA)	Balanced mix of benefit, feature, CTA, and urgency headlines	"Free Shipping on All Orders" · "Shop Now — Save 40%"
Brand	Includes brand name variants, official site messaging, brand authority	"Official Acme Store" · "Acme — Trusted Since 2010"
Competitor	Positioning against alternatives, comparison-friendly language	"A Better Alternative to [X]" · "Switch & Save 60%"
Generic / Non-Brand	Category-level terms, problem-solution framing	"Best CRM Software 2026" · "{KeyWord:CRM Solutions}"

Pro Tips

💡 Run it 2-3 times per page Each generation produces different creative angles. Run the builder multiple times and cherry-pick the best headlines from each batch.

💡 Use the context field for competitive intelligence Tell the AI about your competitors' weaknesses and your unique advantages. The more specific you are, the sharper the copy.

💡 Try different models for the same page Claude tends to be precise with character counts and structured output. GPT often generates more creative variations. Gemini is the fastest. Mix and match.

💡 CSV export → Google Ads Editor Export to CSV, then import directly into Google Ads Editor for bulk upload. The CSV includes character counts and over/under status for quick QA.

Character Limits

Google Ads enforces strict character limits. The builder validates every asset and flags any that exceed limits:

Element	Max Characters	Max Count per Ad
RSA Headline	30	15 (3 shown)
RSA Description	90	4 (2 shown)
Sitelink Title	25	20 (2-6 shown)
Sitelink Description (per line)	35	2 per sitelink
Callout Text	25	20 (2-6 shown)
Structured Snippet Value	25	10 values per header
Display URL Path	15 each	2 paths

Supported Models

Provider	Model	Speed	Quality	Cost
Anthropic	Claude Sonnet 4.6	Medium	Excellent	~$0.003/run
Anthropic	Claude Opus 4.6	Slower	Exceptional	~$0.015/run
OpenAI	GPT-5.4	Medium	Excellent	~$0.005/run
OpenAI	GPT-5.3 Codex	Fast	Excellent (Code)	~$0.003/run
Google	Gemini 3 Flash	Very Fast	Good	Free tier
Google	Gemini 3 Pro	Medium	Very Good	Free tier

Estimated costs are per generation (~2,000 input tokens + ~1,500 output tokens). Actual costs depend on landing page length and model pricing at time of use.

Security Model

The Google Ads Builder uses a defense-in-depth approach to protect your API keys:

Web Crypto API Encryption (AES-256-GCM)

When you enter an API key, the browser generates a random 256-bit encryption key using crypto.subtle.generateKey(). Your API key is encrypted with this key using AES-GCM mode with a random 12-byte IV. The encrypted ciphertext is stored in sessionStorage — the plaintext API key is never stored anywhere.

Session-Only Storage

Both the encryption key and the encrypted API key are stored in sessionStorage, not localStorage. sessionStorage is scoped to the browser tab and is automatically cleared when the tab is closed. It doesn't persist across sessions, isn't shared between tabs, and can't be accessed by other sites.

Direct API Calls (No Proxy)

API calls go directly from your browser to the AI provider's endpoint. The request never passes through any intermediary server. The builder is a static HTML file — there is no backend to intercept traffic.

Manual Clear

The "Clear Session" button in the app immediately calls sessionStorage.clear(), destroying both the encryption key and the encrypted API key. This is irreversible.

🔍 Verify It Yourself The entire tool is a single HTML file. Right-click → View Source and you'll see every line of code. There are no hidden endpoints, no analytics, no tracking pixels, no external scripts (beyond Google Fonts).

Export Options

Copy Individual

Click the "copy" button on any asset card to copy just that headline, description, or extension to your clipboard.

Copy All

Click "Copy All" to get every generated asset as a newline-separated list. Paste directly into a spreadsheet or document.

Export CSV

Click "Export CSV" to download a structured CSV file with columns:

      csv
Type,Text,CharLimit,CharCount,Status
Headline 1,"Free Shipping on All Orders",30,28,OK
Headline 2,"Save 40% — Limited Time Only",30,29,OK
Description 1,"Shop our award-winning collection...",90,85,OK
Sitelink 1 Title,"New Arrivals",25,12,OK
Callout 1,"Free Returns",25,12,OK
    

Import directly into Google Ads Editor or use as a review sheet for your team.

Part of the Agent

The Google Ads Builder is one tool in the Google Ads Agent ecosystem — an open-source AI agent with 28 custom Python actions and 6 specialized sub-agents that manages Google Ads accounts through the API.

While the full agent handles campaign management, optimization, and reporting through the Google Ads API, the Builder is a standalone client-side tool focused specifically on ad copy generation. It doesn't require Google Ads API credentials — just an AI model API key.

View the full agent on GitHub →

About

Built by John Williams, Senior Paid Media Specialist at Seer Interactive with 15+ years managing $48M+ in digital advertising spend. Former NortonLifeLock (192% YoY paid search growth), Gen Digital, and Farmers Insurance.

Speaker at Hero Conf 2025 on AI applications in advertising. Built through It All Started With A Idea.

GitHub · LinkedIn Launch Post · Free Keywords Article · Feedonomics Feature · X / Twitter · Instagram