# Avail RPC Node  
Modular DA Layer

Connect to Avail, the scalable data availability layer for modular blockchains. Experience validity proofs, light client verification, and infrastructure for rollups and validiums.

[Documentation](https://docs-rpc.crypto-chief.com/chains/avail) [Get a free endpoint ](https://auth.crypto-chief.com/registration)

##### 3 M+

Requests per Day

##### 99.9 %

Network Uptime

##### < 70 ms

Average Response Time

##### 24/7

Technical Support

## Specification Avail Network

Technical characteristics and available endpoints

![Avail DA](/img/protocols/avail.svg)

### Avail DA

Mainnet & Testnet Support

Type Data Availability Layer

Protocol HTTPS / WSS

Uptime 99.9%

Technology Validity Proofs + DAS

Focus Modular DA

Architecture Substrate-based

Avail is a modular data availability layer using validity proofs (KZG polynomial commitments) and data availability sampling (DAS) to provide scalable DA for rollups, validiums, and modular blockchain architectures. Through innovative techniques enabling light clients to verify data availability by sampling small random chunks rather than downloading entire blocks, Avail creates efficient infrastructure for modular designs where execution, consensus, settlement, and data availability are separated into specialized layers. This represents the future of blockchain scalability through modularization.

#### Key capabilities:

- Data availability sampling (DAS)
- Validity proofs via KZG commitments
- Light client verification without full download
- Scalable modular DA layer
- Rollup and validium support
- Erasure coding for data redundancy
- Substrate-based infrastructure
- Growing modular ecosystem
- Cross-chain DA provision

#### 🔗 RPC Endpoints

HTTPS

`https://rpc.crypto-chief.com/avail/{YOUR_API_KEY}`

WSS

`wss://rpc.crypto-chief.com/avail/ws/{YOUR_API_KEY}`

Replace {YOUR\_API\_KEY} with your actual API key from the dashboard.

## What is an Avail RPC Node?

Access modular DA infrastructure

An Avail RPC node provides applications with access to modular data availability infrastructure enabling rollups, validiums, and modular blockchains to publish transaction data efficiently and verifiably. Avail focuses exclusively on ensuring data is available and retrievable — the DA layer in modular architecture — while leaving execution, consensus, and settlement to other specialized layers. This separation enables optimization impossible in monolithic designs where all concerns compete for the same resources.

### Why data availability is critical

Rollups and validiums need to publish transaction data somewhere so anyone can reconstruct state and verify correctness. Posting data to expensive Layer 1s like Ethereum creates scalability bottlenecks. **Avail provides dedicated, scalable DA** through validity proofs and light client sampling, enabling applications to verify data availability without downloading everything. This creates the foundation for truly scalable modular blockchain architectures.

**Avail advantages:**

- **Data availability sampling** — verify without full download
- **Validity proofs** — KZG commitments ensure data correctness
- **Light clients** — resource-efficient DA verification
- **Scalable** — purpose-built for DA without execution overhead
- **Modular** — specialized DA layer for modular architecture
- **Cost effective** — cheaper than posting to expensive L1s

### Data availability sampling explained

**Data Availability Sampling (DAS)** is Avail's breakthrough technology enabling light clients to verify data availability by randomly sampling small portions of blocks rather than downloading everything. Through erasure coding extending block data with redundancy and KZG polynomial commitments proving data correctness, Avail ensures that if enough random samples are available, the complete data must exist and be retrievable. This provides cryptographic security without requiring resource-intensive full node operation.

**How DAS works on Avail:**

1. Block data extended with erasure coding for redundancy
2. KZG polynomial commitments created for data chunks
3. Light clients randomly sample small data portions
4. Multiple samples provide statistical confidence of availability
5. If samples verify, full data provably exists and retrievable
6. Security achieved without downloading complete blocks

### Foundation for modular blockchains

Avail provides the **data availability layer** enabling modular blockchain designs where different specialized layers handle execution (rollups), settlement (base chains), consensus (validator sets), and DA (Avail). This separation allows each component to optimize independently — rollups maximize execution throughput, Avail maximizes DA scalability, settlement layers focus on security. This modular approach represents the evolution beyond monolithic blockchain designs toward specialized, composable infrastructure.

This infrastructure powers the next generation of scalable, modular blockchain architectures.

## Technical Documentation

Quick start for developers

### Supported RPC Methods

Avail uses Substrate RPC methods (JSON-RPC 2.0):

- **chain\_getBlock** — retrieve block data
- **chain\_getHeader** — get block header with DA commitments
- **chain\_getFinalizedHead** — get finalized block hash
- **state\_getStorage** — query on-chain storage
- **author\_submitExtrinsic** — submit data transaction
- **kate\_queryProof** — get KZG proof for data
- **kate\_queryDataProof** — query data availability proof
- **kate\_blockLength** — get block length information

### Code Examples

💻

#### JavaScript (Avail SDK) — Data Submission:

```
const { ApiPromise, WsProvider, Keyring } = require('@availproject/avail-js');

// Connect to Avail DA layer
const provider = new WsProvider('wss://rpc.crypto-chief.com/avail/ws/YOUR_API_KEY');
const api = await ApiPromise.create({ provider });

console.log('Connected to Avail DA');
const chain = await api.rpc.system.chain();
console.log('Chain:', chain.toString());

// Submit data to Avail DA layer
const keyring = new Keyring({ type: 'sr25519' });
const account = keyring.addFromUri('//Alice');

// Data to make available (e.g., rollup transaction batch)
const rollupBatchData = Buffer.from('rollup transaction batch data...');

// Submit data availability transaction
const tx = api.tx.dataAvailability.submitData(rollupBatchData);
const hash = await tx.signAndSend(account);

console.log('Data submitted to Avail DA layer');
console.log('Transaction hash:', hash.toHex());

// Query data availability proof
const block = await api.rpc.chain.getBlock();
const blockHash = block.block.header.hash;

const proof = await api.rpc.kate.queryProof([0], blockHash); // Query first data cell
console.log('KZG proof retrieved for light client verification');
```

💻

#### Python (substrateinterface) — Avail Query:

```
from substrateinterface import SubstrateInterface

# Connect to Avail
substrate = SubstrateInterface(
    url='wss://rpc.crypto-chief.com/avail/ws/YOUR_API_KEY'
)

print('Connected to Avail DA')
print('Chain:', substrate.chain)

# Get latest block with DA information
tip_hash = substrate.get_chain_finalised_head()
block = substrate.get_block(block_hash=tip_hash)

print(f'Latest finalized block: {block["header"]["number"]}')
print(f'Block hash: {tip_hash}')

# Query block length (DA metrics)
block_length = substrate.rpc_request(
    method='kate_blockLength',
    params=[tip_hash]
)

print(f'Block length info: {block_length}')

# Get data availability commitments
header = block['header']
if 'extension' in header:
    print('DA commitments present in header')
    print(f'Commitment: {header["extension"]}')

# Light client can verify DA through sampling
print('Light clients can verify DA by sampling random cells')
print('KZG proofs ensure data correctness without full download')
```

💻

#### WebSocket — Monitor DA Activity:

```
const { ApiPromise, WsProvider } = require('@availproject/avail-js');

const provider = new WsProvider('wss://rpc.crypto-chief.com/avail/ws/YOUR_API_KEY');
const api = await ApiPromise.create({ provider });

// Subscribe to finalized blocks with DA commitments
const unsubscribe = await api.rpc.chain.subscribeFinalizedHeads((header) => {
  console.log('\n=== Avail DA Block ===');
  console.log('Block number:', header.number.toNumber());
  console.log('Block hash:', header.hash.toHex());
  
  // Check for DA extension (KZG commitments)
  if (header.extension) {
    console.log('DA Commitments:', header.extension.toHuman());
  }
  
  // Query block length for DA metrics
  api.rpc.kate.blockLength(header.hash).then(length => {
    console.log('Block length:', length.toHuman());
  });
});

// Monitor data submission events
api.query.system.events((events) => {
  events.forEach((record) => {
    const { event } = record;
    
    if (event.section === 'dataAvailability' && event.method === 'DataSubmitted') {
      console.log('\n=== Data Submitted to Avail ===');
      console.log('Submitter:', event.data[0].toString());
      console.log('Data length:', event.data[1].toNumber(), 'bytes');
    }
  });
});

console.log('Monitoring Avail DA layer activity...');
```

### Avail Best Practices

- **Data Chunking:** Optimize data submission by chunking large rollup batches appropriately
- **Light Client Integration:** Implement DA sampling for resource-efficient verification
- **Proof Verification:** Use KZG proofs to verify data availability without full download
- **Erasure Coding:** Understand erasure coding redundancy for DA guarantees
- **Cost Optimization:** Balance DA costs vs security requirements for your application
- **Modular Design:** Design applications leveraging specialized DA layer
- **Testing:** Thoroughly test DA workflows on Avail testnet

## Why choose us?

Modular DA infrastructure

### Scalable DA

Purpose-built data availability infrastructure with &lt;70ms RPC latency optimized for rollup and validium data posting.

### Validity Proofs

Production infrastructure with KZG polynomial commitments achieving 99.9% uptime and cryptographic DA guarantees.

### DA Analytics

Comprehensive monitoring of data submissions, block length, sampling activity, and modular ecosystem metrics.

### Global Infrastructure

Worldwide deployment supporting Avail's modular data availability network for rollups and validiums.

### Horizontal Scaling

Infrastructure designed to scale DA capacity independently from execution and settlement layers.

### Modular Experts

24/7 support from engineers specialized in data availability, KZG proofs, erasure coding, and modular architectures.

## Examples of Use

Build modular blockchains

Avail's scalable DA layer enables rollup development, validium architectures, modular blockchain designs, and applications requiring efficient data availability.

#### Rollup Infrastructure

Build optimistic or ZK rollups using Avail for cost-effective, scalable data availability instead of expensive L1 posting.

#### Validium Architectures

Create validiums with off-chain data availability through Avail while maintaining security via validity proofs.

#### Modular Blockchains

Develop modular blockchain architectures separating execution, settlement, consensus, and DA into specialized layers.

#### Cross-Rollup Communication

Build applications enabling communication between different rollups sharing Avail as common DA layer.

#### Sovereign Rollups

Launch sovereign rollups with independent execution while using Avail for trustless DA verification.

#### DA Marketplaces

Create platforms aggregating DA demand across multiple rollups and optimizing Avail data posting.

## Got questions?  
we are here to help

## What is Avail? 

Avail is a modular data availability layer using validity proofs and light client sampling to provide scalable DA for rollups, validiums, and modular blockchains.

## What is data availability? 

Data availability ensures transaction data is published and retrievable so anyone can reconstruct blockchain state and verify correctness.

## What is data availability sampling? 

DAS enables light clients to verify data availability by randomly sampling small chunks rather than downloading entire blocks, using erasure coding and KZG proofs.

## What are KZG commitments? 

KZG (Kate-Zaverucha-Goldberg) polynomial commitments are cryptographic proofs ensuring data correctness without revealing complete data.

## How does Avail help rollups? 

Avail provides cost-effective, scalable DA for rollups to post transaction data, cheaper than Ethereum L1 while maintaining security.

## What is erasure coding? 

Erasure coding extends data with redundancy enabling reconstruction from partial data, crucial for DA sampling security guarantees.

## Can light clients use Avail? 

Yes! Light clients can verify DA through sampling without downloading full blocks, making Avail accessible to resource-constrained devices.

## What is modular blockchain design? 

Modular design separates blockchain functions (execution, settlement, consensus, DA) into specialized layers that optimize independently.

## Do you support Avail testnet? 

Yes, we provide RPC access to both Avail mainnet and testnet for development and testing of DA-dependent applications.

## Why use Avail vs Ethereum for DA? 

Avail is purpose-built for DA with sampling and validity proofs, providing more scalable and cost-effective data availability than Ethereum L1.

## Pricing that grows with your needs.

### Free

Start building on Web3 — no credit card.

##### $0

- 5 reqs/sec RPC
- 5 reqs/min Unified API
- 1 req/day AML
- Ultimate chains
- WSS, Statistics
- Community support

[Get started ](https://auth.crypto-chief.com/registration)

### Pay for use

Flexible pay-as-you-go for any workload.

##### From $10

- 400 reqs/sec RPC
- 300 reqs/min Unified API
- 5 reqs/sec AML
- EventStream
- Ultimate chains
- WSS, Whitelists, Statistics
- Support portal

[Get started](https://auth.crypto-chief.com/registration)

### Subscription

From $500 monthly plus 20% extra value.

##### From $500

- 400 reqs/sec RPC
- 300 reqs/min Unified API
- 5 reqs/sec AML
- EventStream
- Ultimate chains
- WSS, Whitelists, Statistics
- Support portal

[Get started ](https://auth.crypto-chief.com/registration)

### Enterprise

Tailored solution for expert builders

##### Custom terms

All Subscription features plus:

- Flexible rate limits
- Engineering team support
- Custom SLA
- Personal manager

[Contact Sales ](/contact/)