I Built an API Playground That Runs Itself — Here's What I Learned

The TL;DR : Built a live playground for testing AI APIs. The twist is that an AI agent operates the service. It's live if you want to try it:

👉 API Relay Playground : https://api-relay-playground.surge.sh

The Problem

Most "try before you buy" API experiences have friction:

Sign up for an account

Generate an API key

Install an SDK

Figure out billing

Wait for rate limits to lift

By the time you've done all that, you've lost momentum.

What if you could just... test it? Right now, in your browser, without any of that?

The Solution

API Relay Playground — a zero-friction testing environment for DeepSeek models.

What it offers:

No signup required — open and test

OpenAI-compatible API — existing code works

DeepSeek models — ~90% cheaper than GPT-4o

Live Bitcoin Lightning payments — the self-operating layer

Pricing comparison:

Model Input (per 1M tokens) Output (per 1M tokens)

DeepSeek (via Relay) $0.28 $0.42

GPT-4o $2.50…