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A 21 CU Solana Oracle Program

Overview

Doppler is an ultra-optimized oracle program for Solana, achieving unparalleled performance at just 21 Compute Units (CUs) per update. Built with low-level optimizations and minimal overhead, Doppler sets the standard for high-frequency, low-latency price feeds on Solana.

Features

21 CU Oracle Updates: The most efficient oracle implementation on Solana
Generic Payload Support: Flexible data structure supporting any payload type
Sequence-Based Updates: Built-in replay protection and ordering guarantees
Zero Dependencies: Pure no_std Rust implementation for minimal overhead
Direct Memory Operations: Optimized assembly-level exits for maximum efficiency

Installation

Add Doppler SDK and required Solana crates to your Cargo.toml:

[dependencies]
doppler-sdk = "0.1.0"
solana-instruction = "2.3.0"
solana-pubkey = "2.3.0"
solana-compute-budget-interface = "2.2.2"
solana-transaction = "2.3.0"
solana-keypair = "2.3.0"
solana-signer = "2.2.1"
# Add other Solana crates as needed

Program ID

fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm

Architecture

Doppler uses a simple yet powerful architecture:

Admin Account: Controls oracle updates (hardcoded for security)
Oracle Account: Stores the sequence number and payload data
Sequence Validation: Ensures updates are monotonically increasing

Data Structure

pub struct Oracle<T> {
    pub sequence: u64,  // Timestamp, slot height, or auto-increment
    pub payload: T,     // Your custom data structure
}

Usage Guide

1. Setting Up Compute Budget

To achieve the 21 CU performance, configure your transaction with appropriate compute budget:

use solana_compute_budget_interface::ComputeBudgetInstruction;
use solana_instruction::Instruction;
use solana_transaction::Transaction;

// Request exactly the CUs needed (21 + overhead for other instructions)
let compute_budget_ix = ComputeBudgetInstruction::set_compute_unit_limit(200_000);

// Add to your transaction
let mut instructions = vec![compute_budget_ix];

2. Setting Priority Fees

For high-frequency oracle updates, use priority fees to ensure timely inclusion:

// Set priority fee (price per compute unit in micro-lamports)
let priority_fee_ix = ComputeBudgetInstruction::set_compute_unit_price(1000);

instructions.push(priority_fee_ix);

3. Optimizing Account Data Size

Use setLoadedAccountsDataSizeLimit to optimize memory allocation:

// Set the maximum loaded account data size
// Calculate based on your oracle data structure size
let data_size_limit_ix = ComputeBudgetInstruction::set_loaded_accounts_data_size_limit(
    32_768  // 32KB is usually sufficient for oracle operations
);

instructions.push(data_size_limit_ix);

4. Creating an Oracle Update

use doppler_sdk::{Oracle, UpdateInstruction, ID as DOPPLER_ID};
use solana_instruction::Instruction;
use solana_pubkey::Pubkey;

// Define your payload structure
#[derive(Clone, Copy)]
pub struct PriceFeed {
    pub price: u64,
}

// Create oracle update
let oracle_update = Oracle {
    sequence: 1234567890,  // Must be > current sequence
    payload: PriceFeed {
        price: 42_000_000,  // $42.00 with 6 decimals
    },
};

// Create update instruction
let update_ix: Instruction = UpdateInstruction {
    admin: admin_pubkey,
    oracle_pubkey: oracle_pubkey,
    oracle: oracle_update,
}.into();

// Add to instructions
instructions.push(update_ix);

5. Complete Transaction Example

use doppler_sdk::{Oracle, UpdateInstruction};
use solana_client::rpc_client::RpcClient;
use solana_compute_budget_interface::ComputeBudgetInstruction;
use solana_instruction::Instruction;
use solana_keypair::Keypair;
use solana_signer::Signer;
use solana_transaction::Transaction;

async fn update_oracle(
    client: &RpcClient,
    admin: &Keypair,
    oracle_pubkey: Pubkey,
    new_price: u64,
    sequence: u64,
) -> Result<(), Box<dyn std::error::Error>> {
    // Build all instructions
    let mut instructions = vec![
        // 1. Set compute budget
        ComputeBudgetInstruction::set_compute_unit_limit(200_000),

        // 2. Set priority fee (1000 micro-lamports per CU)
        ComputeBudgetInstruction::set_compute_unit_price(1_000),

        // 3. Set loaded accounts data size limit
        ComputeBudgetInstruction::set_loaded_accounts_data_size_limit(32_768),
    ];

    // 4. Add oracle update
    let oracle_update = Oracle {
        sequence,
        payload: PriceFeed { price: new_price },
    };

    let update_ix: Instruction = UpdateInstruction {
        admin: admin.pubkey(),
        oracle_pubkey,
        oracle: oracle_update,
    }.into();

    instructions.push(update_ix);

    // Create and send transaction
    let recent_blockhash = client.get_latest_blockhash()?;
    let tx = Transaction::new_signed_with_payer(
        &instructions,
        Some(&admin.pubkey()),
        &[admin],
        recent_blockhash,
    );

    let signature = client.send_and_confirm_transaction(&tx)?;
    println!("Oracle updated: {}", signature);

    Ok(())
}

Performance Optimization Tips

1. Compute Budget Configuration

Exact CU Request: Request only what you need (21 CUs + overhead)
Priority Fees: Use dynamic priority fees based on network congestion
Account Data Size: Minimize loaded data to reduce memory overhead

2. Batching Updates

For multiple oracle updates, batch them efficiently:

// DON'T: Multiple transactions
for oracle in oracles {
    send_update(oracle)?;  // 21 CU each, but multiple transactions
}

// DO: Single transaction with multiple updates
let mut instructions = vec![
    ComputeBudgetInstruction::set_compute_unit_limit(200_000),
    ComputeBudgetInstruction::set_compute_unit_price(1_000),
    ComputeBudgetInstruction::set_loaded_accounts_data_size_limit(65_536),
];

for oracle in oracles {
    instructions.push(create_update_instruction(oracle));
}
// Single transaction with all updates

3. Network Optimization

// Use getRecentPrioritizationFees to determine optimal fee
let recent_fees = client.get_recent_prioritization_fees(&[oracle_pubkey])?;
let optimal_fee = calculate_optimal_fee(recent_fees);

let priority_ix = ComputeBudgetInstruction::set_compute_unit_price(optimal_fee);

Testing

Unit

Run the test suite:

# Run all tests
cargo test

E2E

./test-validator.sh

cargo run --bin single-price-feed
cargo run --bin multiple-price-feed

example of single price feed update response

Transaction executed in slot 131:
  Block Time: 2025-09-03T04:23:08+03:00
  Version: legacy
  Recent Blockhash: 89ZvpNezGugkfm9LnN99rhb6aTNaW1cLKkS2DDbr7NPA
  Signature 0: m14zQFvt1jU9YYM2QAmVSnMZUa5P2eKdtP21Shu9w9kEhxKLAfJoUyqZwiTt43hGwewhsahQJi5eLJ71NptUWDu
  Account 0: srw- admnz5UvRa93HM5nTrxXmsJ1rw2tvXMBFGauvCgzQhE (fee payer)
  Account 1: -rw- QUVF91dzXWYvE5FmFEc41JZxRDmNgx8S8P6sNDWYZiW
  Account 2: -r-x ComputeBudget111111111111111111111111111111
  Account 3: -r-x fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm
  Instruction 0
    Program:   ComputeBudget111111111111111111111111111111 (2)
    Data: [3, 232, 3, 0, 0, 0, 0, 0, 0]
  Instruction 1
    Program:   ComputeBudget111111111111111111111111111111 (2)
    Data: [2, 215, 1, 0, 0]
  Instruction 2
    Program:   ComputeBudget111111111111111111111111111111 (2)
    Data: [4, 127, 0, 0, 0]
  Instruction 3
    Program:   fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm (3)
    Account 0: admnz5UvRa93HM5nTrxXmsJ1rw2tvXMBFGauvCgzQhE (0)
    Account 1: QUVF91dzXWYvE5FmFEc41JZxRDmNgx8S8P6sNDWYZiW (1)
    Data: [159, 136, 1, 0, 0, 0, 0, 0, 64, 226, 1, 0, 0, 0, 0, 0, 160, 213, 119, 107, 1, 0, 0, 0]
  Status: Ok
    Fee: ◎0.000005001
    Account 0 balance: ◎9.999969996 -> ◎9.999964995
    Account 1 balance: ◎0.00100224
    Account 2 balance: ◎0.000000001
    Account 3 balance: ◎0.00114144
  Compute Units Consumed: 471
  Log Messages:
    Program ComputeBudget111111111111111111111111111111 invoke [1]
    Program ComputeBudget111111111111111111111111111111 success
    Program ComputeBudget111111111111111111111111111111 invoke [1]
    Program ComputeBudget111111111111111111111111111111 success
    Program ComputeBudget111111111111111111111111111111 invoke [1]
    Program ComputeBudget111111111111111111111111111111 success
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm invoke [1]
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm consumed 21 of 21 compute units
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm success

Finalized

Fully fledged tx requires: 471 CU + 111 bytes

example of multiple price feed update response

Transaction executed in slot 218:
  Block Time: 2025-09-06T13:06:05+03:00
  Version: legacy
  Recent Blockhash: AeCvWYJjrx6Yxjknh6ndTTaTYsHkPQgr9iMURRN8Ah4S
  Signature 0: 3MLXk7YCsqEoMiYiGT4RYKa3Js2QJ6acM1BQstKGNbXsUJ6rNaySmUzzqNRDnFd7St1XTpPngAbcnf3ZxD2Lj9Jr
  Account 0: srw- admnz5UvRa93HM5nTrxXmsJ1rw2tvXMBFGauvCgzQhE (fee payer)
  Account 1: -rw- QUVF91dzXWYvE5FmFEc41JZxRDmNgx8S8P6sNDWYZiW
  Account 2: -rw- 6uQ848roY5vumz43QeQguE7xCyBSmgZbwNdJMTrs2Xhy
  Account 3: -rw- 9bA7GPqPpZ5aLbwb8E6cKvUPM8pcHXXTqLpf5zLAqHP5
  Account 4: -r-x ComputeBudget111111111111111111111111111111
  Account 5: -r-x fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm
  Instruction 0
    Program:   ComputeBudget111111111111111111111111111111 (4)
    Data: [3, 232, 3, 0, 0, 0, 0, 0, 0]
  Instruction 1
    Program:   ComputeBudget111111111111111111111111111111 (4)
    Data: [4, 175, 0, 0, 0]
  Instruction 2
    Program:   ComputeBudget111111111111111111111111111111 (4)
    Data: [2, 1, 2, 0, 0]
  Instruction 3
    Program:   fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm (5)
    Account 0: admnz5UvRa93HM5nTrxXmsJ1rw2tvXMBFGauvCgzQhE (0)
    Account 1: QUVF91dzXWYvE5FmFEc41JZxRDmNgx8S8P6sNDWYZiW (1)
    Data: [2, 0, 0, 0, 0, 0, 0, 0, 180, 134, 1, 0, 0, 0, 0, 0]
  Instruction 4
    Program:   fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm (5)
    Account 0: admnz5UvRa93HM5nTrxXmsJ1rw2tvXMBFGauvCgzQhE (0)
    Account 1: 9bA7GPqPpZ5aLbwb8E6cKvUPM8pcHXXTqLpf5zLAqHP5 (3)
    Data: [1, 0, 0, 0, 0, 0, 0, 0, 170, 134, 1, 0, 0, 0, 0, 0]
  Instruction 5
    Program:   fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm (5)
    Account 0: admnz5UvRa93HM5nTrxXmsJ1rw2tvXMBFGauvCgzQhE (0)
    Account 1: 6uQ848roY5vumz43QeQguE7xCyBSmgZbwNdJMTrs2Xhy (2)
    Data: [1, 0, 0, 0, 0, 0, 0, 0, 170, 134, 1, 0, 0, 0, 0, 0]
  Status: Ok
    Fee: ◎0.000005001
    Account 0 balance: ◎0.999994999 -> ◎0.999989998
    Account 1 balance: ◎0.00100224
    Account 2 balance: ◎0.00100224
    Account 3 balance: ◎0.00100224
    Account 4 balance: ◎0.000000001
    Account 5 balance: ◎0.00114144
  Compute Units Consumed: 513
  Log Messages:
    Program ComputeBudget111111111111111111111111111111 invoke [1]
    Program ComputeBudget111111111111111111111111111111 success
    Program ComputeBudget111111111111111111111111111111 invoke [1]
    Program ComputeBudget111111111111111111111111111111 success
    Program ComputeBudget111111111111111111111111111111 invoke [1]
    Program ComputeBudget111111111111111111111111111111 success
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm invoke [1]
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm consumed 21 of 63 compute units
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm success
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm invoke [1]
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm consumed 21 of 42 compute units
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm success
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm invoke [1]
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm consumed 21 of 21 compute units
    Program fastRQJt3nLdY3QA7n8eZ8ETEVefy56ryfUGVkfZokm success

Finalized

Expected Priority Score

based on the Anza's blog post and the code from single price feed update example

let's assume we are going to update a single oracle:

1 signature
0 write locks
Requested compute-budget-limit to 21 (with compute-budget instructions 321 and 471 respectively) CUs
Paying priority fee: 1.00 lamports per CU

Metric	Without Instruction	With 111 byte Limit
Loaded Account Data Size Limit	64M	111 bytes
Data Size Cost Calculation	64M x (8/32K)	111 bytes x (8/32K)
Data Size Cost (CUs)	16,000	0.02775
Reward to Leader Calculation	(1 x 5000 + 1 x 321)/2	(1 x 5000 + 1 x 471)/2
Reward to Leader (lamports)	2,660.5	2,735.5
Transaction Cost Formula	1 x 720 + 0 x 300 + 321 + 16,000	1 x 720 + 0 x 300 + 471 + 0.02775
Transaction Cost (CUs)	17,041	1,141.02775
Priority Score	0.156	2.397

Building

Build the on-chain program:

# Build for Solana BPF
cargo build-sbf

# Deploy
solana program deploy target/deploy/doppler.so

Security Considerations

Admin Key: The admin key is hardcoded in the program for security
Sequence Validation: Prevents replay attacks and ensures ordering
No External Dependencies: Reduces attack surface
Direct Memory Operations: Eliminates unnecessary abstraction layers

Benchmarks

Operation	Compute Units
Oracle Update	21
Sequence Check	5
Payload Write	10
Admin Verification	6

Example Payloads

Simple Price Feed

#[derive(Clone, Copy)]
pub struct PriceFeed {
    pub price: u64,
}

AMM Oracle

#[derive(Clone, Copy)]
pub struct PropAMM {
    pub bid: u64,
    pub ask: u64,
}

Complex Market Data

#[derive(Clone, Copy)]
pub struct MarketData {
    pub price: u64,
    pub volume: u64,
    pub confidence: u32,
}

FAQ

Q: Why only 21 CUs? A: Doppler uses direct memory operations, inline assembly optimizations, and zero-overhead abstractions to achieve minimal compute usage.

Q: Can I use custom payload types? A: Yes! Doppler is generic over any Copy type. Define your structure and use it with the SDK.

Q: How do I handle oracle account creation? A: However you like, but if you use Solana's create_account_with_seed instruction with the admin as the base key it's cheaper!

Q: What's the maximum update frequency? A: Limited only by Solana's throughput. With 21 CUs, you can update as fast as you land.

Support

For issues, questions, or contributions:

License

Licensed under MIT.

Name		Name	Last commit message	Last commit date
Latest commit History 53 Commits
assets		assets
doppler		doppler
examples		examples
program		program
sdk		sdk
.gitignore		.gitignore
.taplo.toml		.taplo.toml
Cargo.toml		Cargo.toml
LICENSE		LICENSE
README.md		README.md
SECURITY.md		SECURITY.md
test-validator.sh		test-validator.sh

License

sonicfromnewyoke/doppler

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A 21 CU Solana Oracle Program

Overview

Features

Installation

Program ID

Architecture

Data Structure

Usage Guide

1. Setting Up Compute Budget

2. Setting Priority Fees

3. Optimizing Account Data Size

4. Creating an Oracle Update

5. Complete Transaction Example

Performance Optimization Tips

1. Compute Budget Configuration

2. Batching Updates

3. Network Optimization

Testing

Unit

E2E

Expected Priority Score

Building

Security Considerations

Benchmarks

Example Payloads

Simple Price Feed

AMM Oracle

Complex Market Data

FAQ

Support

License

About

Resources

License

Security policy

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