> ## Documentation Index
> Fetch the complete documentation index at: https://cosmos-docs-cosmjs-docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Dynamic Gas Pricing

> Querying on-chain fee markets and the chain registry for gas prices

Some chains implement dynamic gas pricing through fee market modules. Instead of
hardcoding a gas price, CosmJS can query the current base fee from the chain and
adjust automatically.

This is supported for:

* **Osmosis** — EIP-1559 style fee market (`/osmosis.txfees.v1beta1.Query/GetEipBaseFee`)
* **Skip feemarket** — used by Cosmos Hub and other chains (`/feemarket.feemarket.v1.Query/GasPrices`)

## Configuration

Pass a `DynamicGasPriceConfig` instead of a static `GasPrice`:

```typescript theme={"system"}
import {
  SigningStargateClient,
  GasPrice,
  DynamicGasPriceConfig,
} from "@cosmjs/stargate";

const dynamicConfig: DynamicGasPriceConfig = {
  denom: "uatom",
  minGasPrice: GasPrice.fromString("0.005uatom"),
  maxGasPrice: GasPrice.fromString("0.1uatom"),
  multiplier: 1.3,
};

const client = await SigningStargateClient.connectWithSigner(
  "https://rpc.my-chain.network",
  wallet,
  { gasPrice: dynamicConfig },
);

const result = await client.signAndBroadcast(address, messages, "auto");
```

## How It Works

When `"auto"` fee is used with a `DynamicGasPriceConfig`:

1. The chain's fee module is queried for the current base gas price (Osmosis uses `/osmosis.txfees.v1beta1.Query/GetEipBaseFee`; other chains use Skip's `/feemarket.feemarket.v1.Query/GasPrices`)
2. The `multiplier` is applied (default 1.3x) to stay above the minimum
3. The result is clamped between `minGasPrice` and `maxGasPrice`
4. If the query fails, `minGasPrice` is used as a fallback

## DynamicGasPriceConfig Fields

| Field         | Type       | Required | Description                                            |
| ------------- | ---------- | -------- | ------------------------------------------------------ |
| `denom`       | `string`   | Yes      | Token denomination to query the gas price for          |
| `minGasPrice` | `GasPrice` | Yes      | Floor price (also used as fallback if the query fails) |
| `maxGasPrice` | `GasPrice` | No       | Ceiling price. If not set, no maximum is enforced      |
| `multiplier`  | `number`   | No       | Multiplier on the queried price. Defaults to 1.3       |

## Checking Support

You can verify whether a chain supports dynamic gas pricing before configuring
it:

```typescript theme={"system"}
import { checkDynamicGasPriceSupport } from "@cosmjs/stargate";

const supported = await checkDynamicGasPriceSupport(
  queryClient,
  "uatom",
  "cosmoshub-4",
);
```

## Getting Gas Prices from the Chain Registry

CosmJS does not integrate with the
[Cosmos Chain Registry](https://github.com/cosmos/chain-registry) directly, but
you can use it as a source for gas prices. The registry publishes recommended gas
prices for each chain in its `chain.json` files.

### Fetching from the Chain Registry

```typescript theme={"system"}
import { GasPrice } from "@cosmjs/stargate";

const registryUrl =
  "https://raw.githubusercontent.com/cosmos/chain-registry/master/cosmoshub/chain.json";
const response = await fetch(registryUrl);
const chainInfo = await response.json();

const feeToken = chainInfo.fees.fee_tokens.find(
  (t: any) => t.denom === "uatom",
);

const gasPrice = GasPrice.fromString(
  `${feeToken.average_gas_price}${feeToken.denom}`,
);
```

The chain registry typically provides three gas price tiers per token:

| Field               | Description                                       |
| ------------------- | ------------------------------------------------- |
| `low_gas_price`     | Minimum price — may be rejected during congestion |
| `average_gas_price` | Recommended default                               |
| `high_gas_price`    | For priority during high traffic                  |

Using `average_gas_price` is a reasonable default. Use `high_gas_price` for
time-sensitive transactions.

### Libraries That Wrap the Registry

Several community libraries provide typed access to the chain registry:

* [`chain-registry`](https://www.npmjs.com/package/chain-registry) — typed
  chain registry data as an npm package
* [`@chain-registry/client`](https://www.npmjs.com/package/@chain-registry/client) —
  client with fetching and caching

These are external packages, not part of CosmJS.