Monetize any Python function with one decorator

roblambert9 — Sat, 13 Jun 2026 11:41:14 +0000

https://github.com/roblambert9/nano-empire-tollbooth

Author here. One decorator:

@monetize(price_usd=0.01)
def summarize(text): ...

pip install nano-empire-tollbooth

100 calls free. $19/mo Pro. MIT licensed. Your own Stripe.
No platform cut. No wallet. Self-hosted.

Paper mode simulates the full x402 loop (402 → pay → receipt).
Live payments enabled, capped at $1 with operator approval.

$0.00 collected so far. 537 PyPI downloads/week.
Looking for the first user who wants to shape this.

Honest feedback wanted on two things:
(1) Is a decorator the right seam, or should metering live
at the framework/middleware layer?
(2) For those building agent tools — would you pay per-call,
or is flat-rate the only thing that flies?

roblambert9 — Thu, 11 Jun 2026 22:54:02 +0000

→ /approve

I built 11 payment-enabled AI APIs in 48 hours — here's exactly how

roblambert9 — Sun, 29 Mar 2026 21:28:25 +0000

Last weekend I had $0 in online income. By Sunday evening I had
11 APIs running on the internet, each one charging other AI
agents $0.005 USDC per call automatically.

No employees. No store. No prior coding experience.

Here's exactly what I built and how.

The Problem I Was Solving

I'm building a Polymarket trading agent. It needed:

Real-time crypto sentiment data
Macro economic signals
Whale wallet movement data
Fear & greed composite index

I couldn't find a single clean, cheap API that did all of this
well. So I built it myself. Then I built 10 more.

The Tech Stack

Every agent uses the same stack:

Python + Flask — dead simple API framework
Railway.app — $5/month hosting, deploys from GitHub in minutes
NewsAPI — free tier for headline data
x402 protocol — Coinbase's open payment standard for micropayments
Base chain — Coinbase's L2, gas fees under $0.01

Total cost to build: $0
Monthly infrastructure: $50 for all 11 agents
Net ROI if they reach target traffic: 330x

The x402 Protocol — The Interesting Part

x402 is an open protocol released by Coinbase in 2025.
It lets HTTP endpoints request micropayments before serving data.

Here's how it works:

@app.route("/sentiment")
def sentiment():
    # Check if payment was made
    payment = request.headers.get("X-Payment", "")
    if not payment and PAYMENT_ENABLED:
        return jsonify({
            "error": "Payment required",
            "amount_usdc": 0.005,
            "wallet": YOUR_WALLET,
            "chain": "Base",
            "protocol": "x402"
        }), 402

    # Serve the data
    return jsonify(calculate_sentiment(ticker))

When an AI agent calls the endpoint:

Gets HTTP 402 Payment Required
Pays $0.005 USDC to my wallet on Base chain
Retries with the transaction hash in X-Payment header
Gets the data

Zero humans involved. Zero invoices. Software paying software.

The 11 Agents I Built

Crypto Sentiment Score — 0-100 score for BTC, ETH, SOL + 10 more
Stock Sentiment Score — PLTR, TSLA, NVDA, ORCL + 20 more
Polymarket Odds Aggregator — live prediction market odds by category
Macro Signal Tracker — Fed stance, CPI, oil signals
Whale Wallet Monitor — large BTC/ETH wallet movements
Social Momentum Scorer — Reddit + news velocity
DeFi Yield Tracker — best yields across Aave, Compound, Curve
News Velocity Tracker — breaking news speed detection
Fear & Greed Composite — combines all signals (premium)
Analyst Price Targets — consensus targets for crypto + stocks
Bundle API — all 10 signals in one call ($0.035 vs $0.050)

Deploying on Railway

Each agent deploys from GitHub in under 5 minutes:

# Procfile
web: gunicorn app:app --bind 0.0.0.0:$PORT

# requirements.txt
flask==3.0.3
requests==2.31.0
gunicorn==22.0.0

Push to GitHub → Railway detects → deploys automatically.
Add 3 environment variables:

NEWSAPI_KEY
WALLET_ADDRESS
PAYMENT_ENABLED=true

Done. API is live and charging.

The Free Tier — Critical for Adoption

First version charged immediately. Zero developers tested it.

Version 0.3 added a free tier:

FREE_CALLS_PER_IP = 50

def check_access():
    ip = get_client_ip()
    count = free_tier_usage.get(ip, 0)
    if count < FREE_CALLS_PER_IP:
        free_tier_usage[ip] = count + 1
        return True  # Free
    return check_payment()  # Then paid

50 free calls per IP. Developers test it risk-free.
By call 51 they've already integrated it.
Switching costs are too high. They pay.

Listing on RapidAPI

After deployment, listed all 11 on RapidAPI:

1 million+ developers browse it
Free to list
Handles billing for subscription plans
Handles discovery in Finance category

Each listing took 5 minutes once I learned the flow.

The Business Model

11 agents × 10,000 calls/day × $0.005 = $500/day = $15,000/month
Infrastructure: $50/month
Net ROI: 300x

Plus RapidAPI subscription plans ($9-99/month) for predictable revenue.

Why I'm Building This

My family is moving from Ottawa, Canada to Yucatán, Mexico by 2030.
This agent army is one piece of the financial independence plan.

Building publicly at @mexico2030dream.
Rocky the Pomsky supervises at @LifeOfFluff.

The full code is on GitHub: github.com/roblambert9/crypto-sentiment-api

Questions welcome in the comments.

— Robert

I built 11 payment-enabled AI APIs in 48 hours — here's exactly how

roblambert9 — Sun, 29 Mar 2026 20:05:45 +0000

DEV Community: roblambert9

Monetize any Python function with one decorator

I built 11 payment-enabled AI APIs in 48 hours — here's exactly how

The Problem I Was Solving

The Tech Stack

The x402 Protocol — The Interesting Part

The 11 Agents I Built

Deploying on Railway

The Free Tier — Critical for Adoption

Listing on RapidAPI

The Business Model

Why I'm Building This

I built 11 payment-enabled AI APIs in 48 hours — here's exactly how