Free Crypto APIs That Don't Require an API Key

Last updated: March 2026

TL;DR

Most crypto APIs require registration and API keys before you can make your first request. This page lists free, public crypto APIs — including swapapi for token swaps — that you can start using immediately with just curl.

The problem

Why free APIs matter

AI agents can't register for API keys — they can't fill out forms, verify emails, or manage accounts
Hackathon teams need to prototype fast, not spend hours on signup flows
Open-source projects can't ship API keys in code
Students and learners shouldn't need a credit card to learn
Rapid prototyping — test an idea in 5 minutes, not 5 hours

API directory

Free crypto APIs you can use today

swapapi — Token Swaps (our product)

What DEX aggregator API returning executable calldata
Chains 46 EVM chains
Auth None
Rate limit ~30 req/min per IP
URL https://api.swapapi.dev

swap ETH → USDC

$ curl "https://api.swapapi.dev/v1/swap/1?\
tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&\
tokenOut=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&\
amount=1000000000000000000&\
sender=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

CoinGecko — Price Data

What Token prices, market data, historical charts
Auth None for basic endpoints (API key for pro features)
Rate limit ~30 req/min
URL https://api.coingecko.com

get ETH price

$ curl "https://api.coingecko.com/api/v3/simple/price?ids=ethereum&vs_currencies=usd"

Chainlist — RPC Endpoints

What Public RPC URLs for all EVM chains
Auth None
URL https://chainlist.org
Note swapapi also returns RPC URLs in every response (rpcUrls field)

Etherscan (limited) — Block Explorer Data

What Transaction data, contract ABIs, token info
Auth Optional API key (rate limited without)
URL https://api.etherscan.io
Note Works without key but very rate limited (1 req/5s)

DeFi Llama — TVL and Protocol Data

What Total Value Locked, protocol stats, yield data
Auth None
Rate limit Generous
URL https://api.llama.fi

list protocols

$ curl "https://api.llama.fi/protocols"

Comparison

Free vs API-key-required

API	Auth Required	Free Tier	Swap Execution	EVM Chains
swapapi	No	Fully free	Yes (calldata)	46
1inch	Yes	Limited	Yes	~10
0x	Yes	Paid only	Yes	~8
CoinGecko	No (basic)	Yes	No (data only)	N/A
DeFi Llama	No	Yes	No (data only)	N/A

Get started

Getting started

You don't need any setup. Open a terminal and run:

your first swap quote

$ curl "https://api.swapapi.dev/v1/swap/1?\
tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&\
tokenOut=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&\
amount=1000000000000000000&\
sender=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

That's it. No signup, no API key, no SDK to install.