Flip a 1 Cent 1,000 Times at Earthshine

Multi-flip results on the site can now be independently verified — just like API flips.

Verify your multi-flip results

When you flip a coin many times on the site (any /flip-a-coin-N-times/ run), a new “Verify this flip” link appears next to “Details of the result.” It opens a permanent page showing the coin, the heads/tails counts, the timestamp, and the complete flip sequence — recorded for 30 days so anyone can confirm the outcome.

Each multi-flip is generated server-side with a cryptographically secure random source (random_bytes()), so the verification page is genuine third-party proof, not a self-reported result.

Try it: flip on flip-a-coin.com/flip-a-coin-10000-times/ and look for the “Verify this flip” link under the result.

Single flips remain instant and private (generated in your browser), so they don’t produce a verify link — the feature is for multi-flip runs.

flip-a-coin.com gained four new ways to flip a coin from outside the website. If you use ChatGPT, Claude, or build with any AI / HTTP-capable tool, please try them out.

1. The public API is live — use it from anything

A free, unauthenticated JSON API can flip up to 100,000 fair coins per call. Just GET https://flip-a-coin.com/api/flip. Pass heads/tails for custom labels, n for multi-flip, format=binary for compact output. Every flip is generated with a server-side CSPRNG. No API key, CORS enabled, 60 req/min and 5,000/day per IP. Full reference: /api/.

2. Use our Custom GPT in ChatGPT — zero setup

We published Coin Flip — Verified Fair on the ChatGPT GPT Store. Click the link, then just chat: “Flip a coin to decide between pizza and burger.” No setup, no schema, no install — ChatGPT calls our API for you and cites the verify URL. Works on any paid ChatGPT plan (Go, Plus, Pro, Business, Enterprise). Sign-in is required for the GPT’s Action to actually run.

3. Use the MCP server with Claude Desktop, Claude Code & Gemini CLI

We published an official Model Context Protocol server: flip-a-coin-mcp on npm. One command in Claude Code or a small JSON block in Claude Desktop and Claude can flip coins natively. The same package also works with Gemini CLI — Google’s terminal AI tool that speaks MCP (consumer Gemini chat and Gems don’t support third-party MCP yet, but the CLI does). Three tools: flip_coin, flip_coin_many (1–100,000), and verify_flip. Setup details for all three on /ai-integration/.

4. Every API flip gets a verifiable URL

Every call — whether from the GPT, the MCP server, or a direct HTTP request — receives a 16-character flip ID and a citable verify_url that anyone can visit for 30 days. The verify page shows the coin, the count, the timestamp, and the full sequence (up to 10,000 tokens inline for multi-flip runs).

Live sample — a fresh 100-flip Yes/No run we just made for this post: https://flip-a-coin.com/flip/4a004d5a6d0849c3

Documentation

• flip-a-coin.com/ai-integration/ — how to use the GPT, MCP, and copy-paste prompts in any AI assistant.
• flip-a-coin.com/api/ — full developer reference, parameter table, OpenAPI 3.1 schema, and code examples.

You can now embed the coin flip on your own site — no JavaScript, no accounts. Just paste a single <iframe> tag into any blog post, lesson page, or article.

The new Embed the Coin Flip Widget generator lets you:

• Pick from our widget catalog — United States coins (Penny through Presidential Dollar and the 50 State Quarters), Flip a Coin.com’s own Decision Making Coins (Heads/Tails, Yes/No, Go/Stay, and others), and selected cryptocurrencies (Bitcoin, Cardano).
• Customize the Heads and Tails labels (e.g., “Pizza” / “Burger”).
• Match your site with auto/light/dark theme, palette or custom #hex background, and adjustable text size.
• Set the iframe width and height to fit your layout.

Every flip is cryptographically fair (crypto.getRandomValues()) and counts separately on our Statistics page. No tracking cookies are set inside the iframe. Works on all modern browsers, including mobile.

Try it now: head over to flip-a-coin.com/widget/, configure your widget, copy the code, and paste it anywhere.