LaserStream’s gRPC offering builds on a Yellowstone-based interface and enhances it with features like historical replay, multi-node failover, and a fully managed environment. LaserStream uses the open source gRPC protocol, ensuring no vendor lock-in and maximum compatibility with existing gRPC implementations.
You can connect either directly with @yellowstone-grpc or use the higher-level Helius LaserStream SDK for added benefits (auto-reconnect, subscription management, error handling, etc.).
Performance Notice: If you experience any lag or performance issues with your LaserStream connection, please refer to the Troubleshooting section for common causes and solutions related to client performance and network optimization.
For production applications, choose the mainnet endpoint closest to your server for best performance. For example, if deploying in Europe, use either the Amsterdam (ams) or Frankfurt (fra) endpoint.
For development and testing, use the devnet endpoint: https://laserstream-devnet-ewr.helius-rpc.com.
Generate a key from the Helius Dashboard. This key will serve as your authentication token for LaserStream.
Professional Plan Required: LaserStream requires a Professional plan. Ensure your Helius account is upgraded to access LaserStream features.
4
Create a Subscription Script
Create index.ts with the following:
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import { subscribe, CommitmentLevel, LaserstreamConfig, SubscribeRequest } from 'helius-laserstream'async function main() { const subscriptionRequest: SubscribeRequest = { transactions: { client: { accountInclude: ['TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA'], accountExclude: [], accountRequired: [], vote: false, failed: false } }, commitment: CommitmentLevel.CONFIRMED, accounts: {}, slots: {}, transactionsStatus: {}, blocks: {}, blocksMeta: {}, entry: {}, accountsDataSlice: [], // Optionally, you can replay missed data by specifying a fromSlot: // fromSlot: '224339000' // Note: Currently, you can only replay data from up to 3000 slots in the past. };// Replace the values below with your actual LaserStream API key and endpointconst config: LaserstreamConfig = { apiKey: 'YOUR_API_KEY', // Replace with your key from https://dashboard.helius.dev/ endpoint: 'https://laserstream-mainnet-ewr.helius-rpc.com', // Choose your closest region} await subscribe(config, subscriptionRequest, async (data) => { console.log(data); }, async (error) => { console.error(error); });}main().catch(console.error);
In the subscribe request, you need to include the following general parameters:
Historical Replay: You can optionally include a fromSlot: string field in the main SubscribeRequest object to replay data from a specific slot onwards. Currently, replay is supported for up to 3000 slots in the past.
Next, you’ll need to specify the filters for the data you want to subscribe to, such as accounts, blocks, slots, or transactions.
Define filters for slot updates. The key you use (e.g., mySlotLabel) is a user-defined label for this specific filter configuration, allowing you to potentially define multiple named configurations if needed (though typically one is sufficient).
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slots: { // mySlotLabel is a user-defined name for this slot update filter configuration mySlotLabel: { // filterByCommitment: true => Only broadcast slot updates at the specified subscribeRequest commitment filterByCommitment: true // interslotUpdates: true allows receiving updates for changes occurring within a slot, not just new slots. interslotUpdates: true }},
Define filters for account data updates. The key you use (e.g., tokenAccounts) is a user-defined label for this specific filter configuration.
If all fields are empty, all accounts are broadcasted. Otherwise:
Fields operate as a logical AND.
Values within arrays act as a logical OR (except within filters, which operate as a logical AND).
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accounts: { // tokenAccounts is a user-defined label for this account filter configuration tokenAccounts: { // Matches any of these public keys (logical OR) account: ["9SHQTA66Ekh7ZgMnKWsjxXk6DwXku8przs45E8bcEe38"], // Matches owners that are any of these public keys owner: ["TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA"], // Filters - all must match (AND logic) filters: [ { dataSize: 165 }, { memcmp: { offset: 0, data: { base58: "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v" } } } ] }},
Define filters for transaction updates. The key you use (e.g., myTxSubscription) is a user-defined label for this specific filter configuration.
If all fields are left empty, all transactions are broadcasted. Otherwise:
Fields operate as a logical AND.
Values within arrays are treated as a logical OR (except for accountRequired, where all must match).
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transactions: { // myTxSubscription is a user-defined label for this transaction filter configuration myTxSubscription: { vote: false, failed: false, signature: "", // Transaction must include at least one of these public keys (OR) accountInclude: ["86xCnPeV69n6t3DnyGvkKobf9FdN2H9oiVDdaMpo2MMY"], // Exclude if it matches any of these accountExclude: [], // Require all accounts in this array (AND) accountRequired: [] }},
Define filters for block updates. The key you use (e.g., myBlockLabel) is a user-defined label for this specific filter configuration.
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blocks: { // myBlockLabel is a user-defined label for this block filter configuration myBlockLabel: { // Only broadcast blocks referencing these accounts accountInclude: ["86xCnPeV69n6t3DnyGvkKobf9FdN2H9oiVDdaMpo2MMY"], includeTransactions: true, includeAccounts: false, includeEntries: false }},
This functions similarly to Blocks but excludes transactions, accounts, and entries. The key you use (e.g., blockmetadata) is a user-defined label for this subscription. Currently, no filters are available for block metadata—all messages are broadcasted by default.
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blocksMeta: { blockmetadata: {}},
Subscribe to ledger entries. The key you use (e.g., entrySubscribe) is a user-defined label for this subscription. Currently, there are no filters available for entries; all entries are broadcasted.
A: Performance issues with LaserStream connections are typically caused by:
High message volume: The JavaScript client may lag behind when processing too many messages or consuming too much bandwidth. Consider filtering your subscriptions more narrowly to reduce message volume.
Limited local bandwidth: Heavy subscriptions can overwhelm clients with limited network bandwidth. Monitor your network usage and consider upgrading your connection or reducing subscription scope.
Geographic distance: Running subscriptions against servers that are geographically far away can cause performance issues. TCP packets may get dropped on long routes, and you’re limited by the slowest intermediate network path. Solution: Choose the LaserStream endpoint closest to your server location from our available regions (see Endpoints & Regions above).
Client-side processing bottlenecks: Ensure your message processing logic is optimized and doesn’t block the main thread for extended periods.
A: Verify your API key and endpoint are correct and that your network allows outbound gRPC connections to the specified endpoint. Check the Helius status page for any ongoing incidents.
A: Double-check the logical operators (AND/OR) described in the filter sections. Ensure public keys are correct. Review the commitment level specified in your request.
A: Yes, you can define filter configurations under multiple keys (e.g., accounts, transactions) within the same SubscribeRequest object.