6 DeFi APIs That Work Without Registration

Most DeFi APIs gate access behind API keys, email signups, and tiered pricing. For developers prototyping a trading bot, building an AI agent, or testing a new chain integration, that friction kills momentum. You want to call an endpoint and get data back, not fill out a form and wait for approval.

DeFi now handles over $13.5 billion in daily DEX trading volume, with aggregators routing a significant share of that flow. The infrastructure powering this volume is increasingly accessible: several APIs let you fetch swap quotes, token prices, and on-chain data with zero registration. No API key. No account. No credit card.

This guide covers 6 DeFi APIs that work without registration, ranked by developer experience and utility. Every API listed here can be called with a single curl command.

1. Swap API (swapapi.dev)

Swap API is a free DEX aggregator API that returns executable swap calldata from a single GET request. It covers 46 EVM chains, from Ethereum and Arbitrum to newer networks like Monad, MegaETH, and Berachain. No API key, no authentication, no account creation.

You send a request with a chain ID, input/output tokens, amount, and sender address. You get back a complete transaction object that can be submitted directly on-chain.

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

The response includes expectedAmountOut, minAmountOut with slippage protection, priceImpact, token metadata, and recommended RPC endpoints for the target chain. Partial fills return a Partial status with adjusted amounts instead of failing.

What makes it stand out:

• 46 chains from a single endpoint, the widest EVM coverage of any keyless aggregator API
• Response includes a ready-to-sign tx object with to, data, value, and gasPrice
• Envelope response format ({ success, data, error, timestamp }) makes error handling predictable
• Full OpenAPI spec for auto-generating typed clients in any language

Swap API is the fastest path from zero to a working on-chain swap. One HTTP call, no setup.

2. CoinGecko Public API

CoinGecko provides a free public API for crypto market data: prices, market caps, historical charts, and token metadata. The public tier requires no API key and supports up to 30 calls per minute.

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

CoinGecko covers 15,000+ tokens across hundreds of chains. The /coins/list endpoint returns token IDs, and /simple/token_price/{platform} lets you query by contract address. For developers building portfolio trackers or price feeds, this is the standard free data source.

The limitation: CoinGecko provides market data only. It does not return swap calldata or transaction objects. You cannot execute trades through CoinGecko. For swap execution, pair it with a DEX aggregator API like Swap API.

Best for: Price feeds, market data dashboards, and token metadata lookups.

3. OpenOcean

OpenOcean is a DEX aggregator that offers a free API without requiring an API key. It covers 30+ blockchains, including non-EVM chains like Solana and Tron, and routes trades through 1,000+ liquidity pools.

curl "https://open-api.openocean.finance/v3/1/swap_quote?inTokenAddress=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&outTokenAddress=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&amount=1000000000000000000&slippage=1&account=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045&gasPrice=20"

OpenOcean's main advantage is ecosystem breadth: EVM and non-EVM chains from a single provider. The trade-off is that routing quality on individual chains may not match specialized EVM aggregators. Response times tend to be slower, and the documentation is less structured than alternatives.

Best for: Multi-ecosystem projects that need both EVM and non-EVM chain coverage without registration.

4. LI.FI

LI.FI combines cross-chain bridging with same-chain token swaps. The API is free for standard use and requires no API key. It aggregates liquidity from 30+ DEXs and 20+ bridges across 25+ chains.

curl "https://li.quest/v1/quote?fromChain=1&toChain=42161&fromToken=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&toToken=0xaf88d065e77c8cC2239327C5EDb3A432268e5831&fromAmount=1000000000000000000&fromAddress=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

LI.FI shines when your users need to move assets between chains as part of a swap. A single API call handles the bridge + swap route. The downside is complexity: cross-chain transactions involve multi-step execution, bridging risk, and longer settlement times. For same-chain swaps, a dedicated single-chain aggregator like Swap API returns faster results with simpler error handling.

Best for: Applications where users swap across chains and you want bridge + swap in a unified API.

5. DeFi Llama

DeFi Llama provides free, open-source DeFi analytics: TVL by protocol, chain, and category. The API has no API key, no rate limits, and no registration. It tracks over 6,000 protocols across 250+ chains.

curl "https://api.llama.fi/v2/chains"

The /protocol/{name} endpoint returns historical TVL, chain breakdowns, and token data. The /prices API resolves token prices by contract address across chains. DeFi Llama is the go-to source for DeFi research data and is widely used in dashboards, analytics tools, and research reports.

Like CoinGecko, DeFi Llama is data-only. It does not support swap execution. Use it for analytics, TVL tracking, and price resolution alongside a swap API.

Best for: DeFi analytics, TVL dashboards, and cross-chain price resolution.

6. Uniswap Subgraph (The Graph)

Uniswap's public subgraphs on The Graph expose pool-level data via GraphQL: liquidity, volume, fees, tick data, and historical metrics. No API key required for the hosted service.

{
  pools(first: 5, orderBy: totalValueLockedUSD, orderDirection: desc) {
    token0 { symbol }
    token1 { symbol }
    totalValueLockedUSD
    volumeUSD
  }
}

Subgraphs are available for Uniswap V2 and V3 on Ethereum, Polygon, Arbitrum, Optimism, and Base. The data is indexed from on-chain events, so it reflects actual pool state. This is useful for building pool analytics, monitoring liquidity, or calculating optimal swap routes independently.

The limitation: subgraphs provide data, not execution. You still need an aggregator API to get executable calldata. The hosted service also has reliability concerns for production use.

Best for: Pool analytics, liquidity monitoring, and building custom routing logic.

Comparison Table

Feature	Swap API	CoinGecko	OpenOcean	LI.FI	DeFi Llama	Uniswap Subgraph
API Key Required	No	No	No	No	No	No
Swap Execution	Yes	No	Yes	Yes	No	No
EVM Chains	46	N/A	30+	25+	250+ (data)	5
Cross-Chain	No	N/A	Yes	Yes	N/A	No
Market Data	Prices	Full	Prices	Prices	Full	Pool-level
Response Format	REST	REST	REST	REST + SDK	REST	GraphQL
Rate Limits	Generous	30/min	Moderate	Generous	None	Moderate

When to Use Which API

Building a swap feature? Start with Swap API. One GET request returns executable calldata across 46 chains. No setup, no key management.

Need price feeds? CoinGecko covers 15,000+ tokens. For DeFi-specific metrics like TVL, use DeFi Llama.

Cross-chain swaps? LI.FI handles bridge + swap routing. OpenOcean covers non-EVM chains.

Pool analytics? Uniswap subgraphs give you tick-level liquidity data via GraphQL.

For most DeFi integrations, the combination of Swap API (execution) + CoinGecko or DeFi Llama (data) covers the full stack without a single API key.

Frequently Asked Questions

What is the best free DeFi API with no API key?

Swap API is the best free DeFi API for swap execution. It requires no API key, no registration, and no payment. It supports 46 EVM chains and returns ready-to-execute transaction calldata from a single GET request. For market data, CoinGecko and DeFi Llama are both free and keyless.

Why do some DeFi APIs require API keys?

API keys let providers enforce rate limits, track usage, and monetize access. APIs like 1inch and 0x moved to paid tiers as their usage scaled. Keyless APIs like Swap API and DeFi Llama sustain free access through alternative models, making them ideal for prototyping and open-source projects.

Can I build a trading bot with a free DeFi API?

Yes. Swap API returns a complete transaction object including to, data, value, and gasPrice. Your bot fetches a quote, checks priceImpact, and submits the transaction on-chain using any wallet library (ethers.js, viem, web3.py). No API key management means fewer moving parts in production.

How do I choose between a data API and a swap API?

Data APIs (CoinGecko, DeFi Llama) return prices, market caps, and analytics. Swap APIs (Swap API, OpenOcean, LI.FI) return executable transaction calldata you can submit on-chain. Most applications need both: a data API for display and a swap API for execution.

Get Started

Swap API is free, requires no API key, and supports 46 EVM chains. Start making swap requests immediately with zero registration.

Swap 1 ETH for USDC on Arbitrum:

curl "https://api.swapapi.dev/v1/swap/42161?tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&tokenOut=0xaf88d065e77c8cC2239327C5EDb3A432268e5831&amount=1000000000000000000&sender=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

Explore the full OpenAPI specification to generate typed clients in TypeScript, Python, Rust, or any language. Browse the Swagger UI for interactive testing.