Autofill AI Ninja

Tutorial: how to use Autofill AI Ninja

Configure the side panel and fill a form end to end. Not installed yet? Install first.

You do not need a paid OpenAI or Anthropic account. Google AI Studio and Groq Cloud both issue a free API key. Their free tiers are enough for typical extension use (filling forms while you test). No credit card is required. See how to get a free key below.

Choose a fill mode

Open the side panel → Behavior and pick a Fill mode:

Mode When to use API key
Hybrid Default. Heuristics fill obvious fields; the LLM handles the rest Required
AI only Everything goes to the model Required
Heuristics only Offline / no provider. Good for smoke checks Not required

For first-time setup, leave Hybrid selected.

Get a free API key

Hybrid and AI-only modes need a key from some provider. Pick one of the free options below — you do not have to pay for OpenAI or Anthropic to use this extension.

Google AI Studio (recommended)

Gemini models via aistudio.google.com/apikey. Free tier, no credit card.

  1. Open Google AI Studio → API keys.
  2. Sign in with a Google account and accept the terms if prompted.
  3. Click Create API key.
  4. Create a key in a new project (simplest), or pick an existing Google Cloud project. Billing is not required for the free Gemini API quota.
  5. Copy the key and keep it private. You can reveal it again later from the same page.
Recommended model: after you connect this key, set Model to Gemini 3.1 Flash (gemini-3.1-flash). It is the best starting point for this extension — faster, fewer fill mistakes, and still on the free tier.

Groq Cloud

Fast open-source models via console.groq.com/keys. Free tier, no credit card. For testing, keep Llama 3.3 70B Versatile (llama-3.3-70b-versatile) — it is accurate enough for forms and stays within Groq’s free limits.

  1. Open console.groq.com and sign up with email, Google, or GitHub.
  2. Go to API Keys in the sidebar.
  3. Click Create API Key, give it a name (for example autofill-ai-ninja).
  4. Copy the key immediately. Groq shows the full key only once — if you close the dialog without copying, create a new key.
Free quotas and rate limits can change. For filling a handful of forms while you test, either provider is enough. If you later hit a rate limit, wait a minute and run fill again, or switch to the other free provider.

Connect it in the side panel

Needed for Hybrid or AI only:

  1. Expand Connection.
  2. Choose a Provider. For a free key, pick Google AI Studio or Groq Cloud (OpenAI is the catalog default, but it is paid).
  3. Paste the API key you copied above.
  4. Click Test, then Save key.
  5. Pick a Model. For Google AI Studio choose Gemini 3.1 Flash (do not leave an older Flash default if you see one). For Groq, use Llama 3.3 70B Versatile.
  6. Optionally enable remembering the key across restarts, or encrypting keys with a passphrase.

Provider, model, and behavior changes save automatically. API keys still need Save key.

Keys never leave the extension background worker. The page you fill never sees them.

Tune behavior

Setting Suggested start What it does
Value language Follow the page Match page locale, or force a BCP-47 tag
Advance multi-step forms On Clicks Next / Continue after each step
Maximum steps 15 Safety cap (hard max 50)
Maximum rounds per step 24 Fill / repair passes per step
Settle delay (ms) 120 Wait after writes for conditional fields
Fill empty fields only On Skip fields that already have a value
Skip password and payment Off by default Never fill or send those fields to the AI
Turning Fill empty fields only off can send short snippets of existing values (up to 60 characters) to the LLM.

Open a form and fill it

  1. Navigate to a page with a form.
  2. Open the side panel.
  3. Optionally type a Custom request, for example:
    • Phone as 090-XXXX-XXXX
    • User names in Japanese
    • Use a Berlin shipping address
  4. Click Fill this page.

Watch the Progress log for scan, chunk, apply, and step-advance messages.

Other ways to start a fill (same saved settings):

  • Right-click the page → Fill this form with AI
  • Keyboard: Alt+Shift+F

Multi-step forms end to end

With auto-advance enabled:

  1. The extension fills the current step.
  2. It waits for the DOM to settle (conditionals, validation).
  3. It clicks the best forward control (Next / Continue / …).
  4. It detects the next step via a content fingerprint (visible fields + URL + step indicator).
  5. It carries identity values forward (email, name, phone, …) so confirmations match.
  6. It stops when there is no safe next step, the step cap is hit, or only a final submit remains.
Search / lookup fields: after filling a search-like control, the extension waits for a results list or table and clicks the best matching row. Search inputs are not blurred immediately so typeahead panels stay open.

Final-submit controls (Pay, Place order, Checkout) are not clicked by default — review and submit yourself.

If Next fails due to validation errors, those messages are quoted back to the model for one repair round, then Next is retried once.

Everyday tips

  • Leave Custom request empty unless you need a specific format or persona.
  • Prefer Hybrid for speed and cost; use AI only when heuristics miss domain-specific fields. On Google AI Studio, keep Gemini 3.1 Flash for fewer errors.
  • Use Heuristics only for a fully offline pass.
  • If a field is stuck, raise Maximum rounds per step or add a custom request that matches the page’s format hint.
  • If you loaded from GitHub, reload the extension on chrome://extensions after npm run build when the side panel looks stale.
  • Restricted Chrome pages (chrome://, Web Store, etc.) cannot be scripted.

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