Pendle API Overview

Pendle provides a comprehensive API system that enables developers to integrate with the Pendle protocol for trading, analytics, and portfolio management.

Important: Stay up to date with the latest developer updates and get support from our team:

• Telegram: Join t.me/pendledevelopers for all development updates, API changes, and important announcements
• Telegram bot: We have a telegram bot for developers to ask about the API at t.me/peepo_the_engineer_bot
• Discord: Get technical support on our Discord Developer Channel with responses within 24 hours

Understanding Pendle's API System

API Base URL: https://api-v2.pendle.finance/core/docs

Pendle's API consists of two complementary components:

1. Hosted SDK (Transaction Generation)

Purpose: Generate transaction payloads to interact with Pendle smart contracts

Use this when you need to:

• Swap tokens (buy/sell PT, YT)
• Add or remove liquidity
• Mint or redeem PT/YT tokens
• Transfer liquidity between pools
• Roll over PT positions
• ... or any other transactions that interact with Pendle smart contracts

📖 View Hosted SDK Documentation

2. Backend API (Data Queries)

Purpose: Retrieve offchain data for markets, assets, pricing, user positions, and vePendle governance

Use this when you need to:

• Get offchain data for analytics
• Get supported markets list with latest data (TVL, volume, underlying APY, swap fee, ...)
• Get PT/YT/LP/SY asset prices
• Get VePendle data (vePendle, current vote, current vote cap, voter apr, ...)

📖 View Backend API Documentation

Rate Limiting

All Pendle API endpoints are rate-limited to ensure service stability and fair usage.

How Rate Limiting Works

Pendle uses a Computing Unit (CU) based system, every endpoint have a CU cost (could be fixed or dynamic depending on the endpoint). The rate limit is calculated based on the total CU cost of all endpoints.

Each user (IP) has a rate limit of 100 CU per minute, and 200,000 CU per week.

Both limits apply simultaneously. You must stay within both the per-minute AND weekly limits to avoid rate limiting.

Example: If an endpoint costs 5 CU, you can call it:

• 20 times per minute (100 ÷ 5 = 20)
• 40,000 times per week (200,000 ÷ 5 = 40,000)

Computing Unit Costs

Most RESTful API endpoints have fixed costs (typically 1-5 CU) wheare HostedSdk has dynamic costs depends on the number of aggregators used. Check the swagger documentation for specific costs - they're displayed in the "CU" box before each endpoint description.

More on computing unit costs for HostedSdk can be found in HostedSdk.mdx.

Rate Limit Headers

Our endpoints return following headers to help you monitor your usage:

Header	Description
X-Computing-Unit	CU cost of this request
X-RateLimit-Limit	Maximum CU per minute (e.g., 100 for free tier)
X-RateLimit-Remaining	CU remaining in current minute window
X-RateLimit-Reset	Unix timestamp when minute limit resets
X-RateLimit-Weekly-Limit	Maximum CU per week (e.g., 200,000 for free tier)
X-RateLimit-Weekly-Remaining	CU remaining in current week window
X-RateLimit-Weekly-Reset	Unix timestamp when week limit resets

Example response:

x-computing-unit: 25
x-ratelimit-limit: 100
x-ratelimit-remaining: 75
x-ratelimit-reset: 1724206817
x-ratelimit-weekly-limit: 200000
x-ratelimit-weekly-remaining: 175000
x-ratelimit-weekly-reset: 1724206817

I get rate limited, what should I do?

Our rate limit was designed so that most users can use the API without facing any rate limiting issues unless you are calling the API unreasonably fast.

So before requesting increased rate limits, please make sure you are not calling the API at an unreasonable rate, follow our best practices and examples.

If after all that, you are still getting rate limited, you can consider upgrading your plan, details below.

API Pricing Plans

If you need higher rate limits, we offer flexible paid plans that scale with your needs.

Pricing Structure

Our pricing is simple and scalable: $10/week = 500 CU/min + 1,000,000 CU/week

You can purchase multiple units to scale your rate limits based on your application's requirements:

Weekly Cost	CU per Minute	Weekly CU Limit
$0 (Free)	100	200,000
$10	500	1,000,000
$20	1,000	2,000,000
$30	1,500	3,000,000
$40	2,000	4,000,000

Pricing Model:

• Each $10/week adds +500 CU/min and +1,000,000 CU/week to your limits
• Scale up to $40/week (2,000 CU/min, 4M CU/week) through our standard plans

Example: If you want to use 1,000,000 CU per week and you want to use the API for 4 weeks, it would be $10 * 4 =$40.

If you want to use 2,000,000 CU per week and you want to use the API for 8 weeks (about 2 months), it would be $20 * 8 =$160.

How to upgrade your plan?

Contact us via Discord, and provide the following information:

1. Your expected weekly usage
2. How long you need the API for
3. Send USDC/USDT to our address (we will provide the address after you contact us)

API Updates and deprecation notice

• Deprecation Notice: Breaking changes announced at least 30 days in advance, follow Telegram Developer Channel for announcements

Code Examples and Resources

Official Examples

• Hosted SDK Demo - Transaction generation examples
• Backend API Demo - Data query examples

Getting Help

1. Documentation: Start with API Overview, Hosted SDK or Backend API docs
2. API Reference: Explore endpoints at Swagger UI
3. Examples: Check GitHub examples

Frequently Asked Questions

Q: When should I use Hosted SDK vs RESTful API?

A: Use Hosted SDK when you need to send transactions to the blockchain (swaps, liquidity operations, mints/redeems). Use RESTful API when you need to get data (market info, prices, positions). See Overview.

Hosted SDK FAQ

Q: How do I know the exact output amount before sending a transaction?

A: There is no way to know the exact output amount before sending a transaction. All the output amounts are calculated based on the current market conditions, and they are subject to change until the transaction is executed, you can control how much the output amount can vary compared to the expected amount by setting the slippage parameter.

Q: Why do I get different results each time I call the same endpoint?

A: Market conditions change constantly. Each call reflects the current state of liquidity pools and aggregator routes.

Q: Do I need to approve tokens before using the Hosted SDK?

A: Short answer is No, long answer is Yes.

• Short answer: You don't need to approve/have enough token balance to call hosted sdk API.
• Long answer: Our hosted sdk try its best to return a most correct route by simulating all the routes it returns, however if you don't have enough token or approval, the hosted sdk couldn't simulate the call, the return route will be preview route, which could be different from actual route. So TLDR: if you have enough approval and balance, SDK will beable to simulate -> more accurate route. Otherwise, all routes are preview routes.

Also, the API response includes a requiredApprovals field listing tokens that need approval. Approve these tokens to the router contract before sending your transaction.

Q: How do I reduce Computing Unit costs when using aggregators?

A: Obtain API keys from aggregator partners (KyberSwap, Odos, OKX) and pass them in request headers. This reduces that aggregator's CU cost to 0. See Reducing Aggregator Costs.

Q: What happens if I don't specify which aggregators to use?

A: If enableAggregator=true but no aggregators parameter is provided, the system will use a preset set of aggregators will be used, which may change over time for optimization.

Q: Can I swap any PT to any other PT?

A: Not all PT pairs are swappable. Try using the Convert API, if the swap is not supported, the API will return an error.

Q: What does the needScale parameter do?

A: Set needScale=true only when your input amounts are updated on-chain (e.g., using contract balance). When enabled, buffer your input amount by ~2% to account for changes during transaction execution. Only applicable to swap actions.

Q: What is priceImpact and does it include slippage?

A: priceImpact is the effect your trade size has on the market price - it's included in the output amount. Slippage is different - it's caused by market movement between API call and transaction execution. You set slippage parameter as maximum tolerance (e.g., 0.01 = 1%). See BackendApi.mdx - Price Impact vs Slippage.

Q: What's the difference between "Add liquidity" and "Add liquidity ZPI"?

A:

• Add liquidity: Adds liquidity and receives only LP tokens
• Add liquidity ZPI (Zero Price Impact): Adds liquidity while keeping the generated YT tokens

Q: Can I transfer liquidity between different pools?

A: Yes! Use the Convert API with your current position (LP + PT + YT) as tokensIn and the target market as tokensOut.

Q: What contract is the to address in the transaction response?

A: The to address is typically the Pendle Router contract. This contract is upgradeable, so the address may change over time. Always use the address returned by the API - never hardcode it.

Q: How do I decode the transaction data to see what function is being called?

A: The response includes contractParamInfo with:

• method: Function name (e.g., "swapExactTokenForPt")
• contractCallParamsName: Parameter names
• contractCallParams: Parameter values

console.log('Method:', response.contractParamInfo.method);
console.log('Params:', response.contractParamInfo.contractCallParams);

Q: Is the router address guaranteed to stay the same?

A: No, the router may be updated for protocol improvements. Always use the tx.to address from the API response. Changes will be announced publicly via the Telegram Developer Channel.

Q: Can I use the same transaction data multiple times?

A: No. Transaction data is specific to current market conditions. Always generate fresh transaction data immediately before sending. Reusing old data will likely fail or give suboptimal results.