# Gas Price API
The Gas Price API gives you the gas price needed to have a certain probability to qualify for inclusion in the next block (for Ethereum or Bitcoin) or the next ∼10 seconds, depending on the chain. Need a high probability of being confirmed at the expense of spending extra gas? Use the 99% probability prediction. Don't mind if the transaction takes longer to confirm? Use the 50% probability prediction.
## Gas Platform currently supports the following networks
Click on any `chainID` in the table below to access the corresponding API.
{% hint style="success" %}
**43 chains** currently supported.
{% endhint %}
You can view [an introductory video on Gas Platform here](https://youtu.be/_Szpb1GTQ6k).
{% hint style="info" %}
Looking for a network that's not currently supported? Let us know by using our contact form [here](https://www.blocknative.com/contact-us).
{% endhint %}
## Authentication
A valid Blocknative API key is OPTIONAL in the `Authorization` Header of every request. Request an API key [here](https://www.blocknative.com/request-api-key).
A free API key is recommended for more generous rate limits and future features.
## API Endpoint
`GET` `https://api.blocknative.com/gasprices/blockprices`
Returns a range of confidence intervals for gas prices needed to qualify a transaction for inclusion in the next block or next ∼10 seconds, depending on the chain. The order of confidence intervals is subject to change.
## Rate Limits
Each endpoint is limited to provide updated results once per second for paid tier API keys, or every 5 seconds for free tier API keys. Polling faster than these rates may deliver stale data.
## Request
### Example request
*This will provide Ethereum Mainnet estimates across all confidence levels by **default**.*
{% code overflow="wrap" %}
```
curl -H 'Authorization: optional-apikey-here' 'https://api.blocknative.com/gasprices/blockprices'
```
{% endcode %}
Or without the optional apikey
{% code overflow="wrap" %}
```
curl 'https://api.blocknative.com/gasprices/blockprices'
```
{% endcode %}
### Example using `ChainID`
curl 'https://api.blocknative.com/gasprices/blockprices?chainid=1514'
### Example using `System` and `Network` parameters
*To know which parameters to use, refer to the list under* [*`/chains`*](https://api.blocknative.com/chains)*.*
{% code overflow="wrap" %}
```
curl 'https://api.blocknative.com/gasprices/blockprices?system=story&network=mainnet'
```
{% endcode %}
### Example using custom `confidence` level request
{% code overflow="wrap" %}
```
curl -H 'Authorization: optional-apikey-here' 'https://api.blocknative.com/gasprices/blockprices?chainid=1&confidenceLevels=50&confidenceLevels=70&confidenceLevels=80&confidenceLevels=90&confidenceLevels=99'
```
{% endcode %}
An alternative format for confidence levels is
{% code overflow="wrap" %}
```
curl -H 'Authorization: optional-apikey-here' 'https://api.blocknative.com/gasprices/blockprices?chainid=1&confidenceLevels=50,70,80,90,99'
```
{% endcode %}
### Example Response Payload
```json
{
"system": "ethereum",
"network": "main",
"unit": "gwei",
"maxPrice": 25,
"currentBlockNumber": 19420156,
"msSinceLastBlock": 8303,
"blockPrices": [
{
"blockNumber": 19420156,
"estimatedTransactionCount": 58,
"baseFeePerGas": 20.118985095,
"blobBaseFeePerGas": 1e-9,
"estimatedPrices": [
{
"confidence": 99,
"price": 20,
"maxPriorityFeePerGas": 0.1,
"maxFeePerGas": 24.12
},
{
"confidence": 95,
"price": 20,
"maxPriorityFeePerGas": 0.09,
"maxFeePerGas": 24.11
},
{
"confidence": 90,
"price": 20,
"maxPriorityFeePerGas": 0.09,
"maxFeePerGas": 24.11
},
{
"confidence": 80,
"price": 20,
"maxPriorityFeePerGas": 0.08,
"maxFeePerGas": 24.1
},
{
"confidence": 70,
"price": 20,
"maxPriorityFeePerGas": 0.07,
"maxFeePerGas": 24.09
}
]
}
]
}
```
### Header
| Name | Type | Description |
| ------------- | ------ | ----------------------------------------------------------- |
| Authorization | string | OPTIONAL
if used, must contain a valid apikey
|
{% tabs %}
{% tab title="200 Success" %}
```javascript
{
"system": "ethereum",
"network": "main",
"unit": "gwei",
"maxPrice": Number, // Highest priced transaction in the mempool
"currentBlockNumber": Number, // Block number at time of prediction
"msSinceLastBlock": Number, // Milliseconds since the last block was mined relative to when this data was computed
"blockPrices": [
{
"blockNumber": Number, // Block this prediction is for
"estimatedTransactionCount": Number, // Number of items we estimate will be included in next block based on mempool snapshot
"baseFeePerGas": 1, // Base fee per gas for current block in gwei
"blobBaseFeePerGas": Number // Base fee per gas for blobs for current block in gwei.
"estimatedPrices": [
{
"confidence": Number, // 0-99 likelihood the next block will contain a transaction with a gas price >= to the listed price
"price": Number, // Price in gwei
"maxPriorityFeePerGas": Number, // Max priority fee per gas in gwei
"maxFeePerGas": Number, // Max fee per gas in gwei
},
...,
]
}
]
}
```
{% endtab %}
{% tab title="401 Key invalid or not provided" %}
```
{
"msg": "Optional authorization header must contain a valid apikey"
}
```
{% endtab %}
{% tab title="429 Rate limit exceeded. Refer to the headers for when to retry the request." %}
```
{ "msg":"Too Many Requests" }
```
{% endtab %}
{% endtabs %}
### Query Parameters
| Name | Type | Description |
| ---------------- | ------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| confidenceLevels | integer | Override default confidence levels (99,95,90,80,70) in response with up to 5 confidence levels.
Ethereum Mainnet confidence levels are from 1 - 99 (increments of 1)
Other chains confidence levels are any from (99,95,90,80,70,50)
|
| chainid | integer | The network chain ID. Default is 1 (Ethereum Mainnet). |
| system | string | The chain ecosystem (e.g., `"ethereum"`, `"story"`, `"polygon"`, etc.) |
| network | string | The specific network within the system (e.g., `"mainnet"`, `"sepolia"` etc.). To know which parameters to use, refer to the list under [`/chains`](https://api.blocknative.com/chains). |
### Type0 and Type2 Transactions
Type0 transactions (Pre EIP-1559) should utilize the `Price` number under each confidence level. Type2 transactions (EIP-1559) should utilize the values for `maxPriorityFeePerGas` (also known as the "tip") and `maxFeePerGas` .
## Description of Terms
| Term | Description |
| --------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| maxPrice | Highest priced transaction in the mempool. |
| currentBlockNumber | Block number at the time of prediction. |
| msSinceLastBlock | Milliseconds since the last block was mined relative to when data was computed. |
| blockNumber | Block this prediction is for. |
| estimatedTransaction Count | Number of items we estimate will be included in next block based on mempool snapshot. |
| baseFeePerGas | Base fee per gas for current block in gwei. (Only type2 transactions Post EIP-1559 have this value and it's burned by the network upon transaction success). |
| blobBaseFeePerGas | Base fee per gas for blobs for current block in gwei. (Only type3 transactions Post EIP-4844 have this value and it's burned by the network upon transaction success). |
| estimatedPrices -> confidence | The likelihood the next block will contain a transaction with a **price** >= to the listed **price.** |
| estimatedPrices -> price | Price in Gwei (used for type0 transactions: Pre EIP-1559). |
| estimatedPrices -> maxPriorityFeePerGas | Max priority fee per gas in gwei also known as the "tip" (used for type2 transactions: EIP-1559). |
| estimatedPrices -> maxFeePerGas | Max fee per gas in gwei (used for type2 transactions: EIP-1559). **maxFeePerGas** is computed from **baseFeePerGas** prediction ∼10 seconds after the current pending block + **maxPriorityFeePerGas.** |