Helius Launches balance-at API: Query Any Solana Wallet's Historical Balance in One Call

Helius hSOL$77.24-4.5% launched the balance-at API endpoint on June 24, 2026, a single REST call that returns any Solana wallet's exact SOL or SPL token balance at any past point in time, specified by Unix timestamp, UTC datetime, or slot number. The endpoint ships as part of Helius's Wallet API and is currently in beta.

Until now, developers who needed historical balance data for accounting, tax reporting, or governance snapshots had to either build and maintain their own indexing infrastructure or approximate balances by replaying transaction history. Neither option was simple, cheap, or reliable at scale.

"Get a wallet's balance at any point in time," Helius posted on June 24. "The new balance-at endpoint returns a wallet's exact SOL or SPL token balance at a given date or slot."

How the balance-at Endpoint Works

The endpoint is available at GET /v1/wallet/{wallet}/balance-at on api.helius.xyz. Developers provide a wallet address, a mint address (use So11111111111111111111111111111111111111112 for native SOL), and exactly one time parameter: a Unix timestamp in seconds (time), a UTC datetime string (datetime, formatted as "2025-01-10 19:20:00"), or a specific slot number (slot).

The response includes balance as a human-readable decimal string, balanceRaw as a raw integer for precision-sensitive applications, decimals, and an asOf object containing the slot, blockTime, and signature of the anchor transaction used to confirm the balance. Each request costs 100 credits.

The slot-based query is fully deterministic. Timestamp and datetime queries resolve to the nearest slot, so the asOf field in the response tells callers exactly which slot and transaction the balance was anchored to.

Helius lists the primary use cases as PnL calculation, cost basis and tax lot tracking, airdrop and governance snapshot eligibility checks, dispute resolution, and accounting and audit workflows. The endpoint currently supports one token per request and remains in beta, with Helius noting that APIs and response formats may change.

The Engineering Problem That Took Years to Solve

The announcement came six days after Helius published a detailed engineering post explaining why this capability required rebuilding Solana's archival data layer from scratch.

Helius CEO mert described the challenge on June 24: "this is one of the gnarliest engineering challenges that exists on Solana — so we solved it for everyone, scale — historical balances for any wallet, for any token, at any time — yes you read that correctly — it took years but it finally exists."

The core problem was structural. Solana's archival history is defined by high-entropy random identifiers — transaction signatures and account public keys that have no temporal locality. Helius had previously used ClickHouse, a columnar database designed for time-series scans. That architecture is the wrong fit for uniformly random point lookups: a single transaction signature query required ClickHouse to read roughly 20 index granules and perform around 60 disk I/Os before any CPU work. Methods like getTransactionsForAddress, which fan out into up to 100 such lookups, pushed latency floors near 100 milliseconds. Large batches approached one full second.

Historical balance reconstruction requires those random lookups at scale and in arbitrary sequence. ClickHouse's columnar layout meant there was no efficient path.

From ClickHouse to a Custom RocksDB System

Helius's solution was to move more than 300 terabytes of Solana archival data off ClickHouse and onto a custom database built on top of RocksDB, published in the June 18 engineering post. The migration compressed storage from roughly 330TB (ClickHouse, compressed) to approximately 190TB, while indexing over 500 billion transactions and 1.3 trillion account-to-transaction index rows.

RocksDB is a key-value library, not a full database. Helius built the query layer on top of it. The system uses two specialized indexes: a signature-to-location index mapping 64-byte transaction signatures to their slot and block position, and a slot-to-block index mapping those locations to the actual transaction data. The Log-Structured Merge tree at the core of RocksDB maintains globally sorted runs after compaction, which enables efficient pruning even for uniformly random key lookups, the same workload that made ClickHouse fail.

The infrastructure runs on purpose-built bare-metal hosts with petabytes of NVMe storage, replicated across multiple regions. Additional tuning included disabling the write-ahead log (archival data can be rebuilt from LaserStream if needed), using direct I/O to eliminate OS page cache contention, deploying a HyperClockCache to replace the standard LRU under high key contention, and using io_uring for parallel multi-key lookups.

The performance improvements were significant. P95 latency for getTransaction dropped from 7ms to 1ms. P95 latency for getTransactionsForAddress dropped from 350ms to 30ms. P99 latency across all archival methods fell more than 10x, from roughly 3 seconds to under 300ms. The infrastructure also handled a sustained 150 Gbit/s getBlock traffic burst for five to six hours during testing.

As Solana Compass previously covered, Triton One took a different approach to the same archival problem in June 2026, open-sourcing SuperBank, a ClickHouse rebuild that uses materialized views to handle Solana's historical ledger. Helius's RocksDB path makes the opposite architectural bet, discarding ClickHouse entirely in favor of a purpose-built key-value store tuned for random-access patterns.

First Ecosystem Integration: Orb Markets

Orb Markets, a Solana block explorer, appears to be the first platform to integrate the endpoint. The Orb team noted on June 24 that historical token balances were live on their platform, allowing users to view how any wallet's balance and value for any token has changed over time.

The balance-at endpoint builds on the infrastructure groundwork that also enables Helius's getTransactionsForAddress method, which was a centerpiece of Helius's Breakpoint 25 keynote and indexes 2.3 trillion rows to make address-level history queries fast. Historical balance reconstruction is a harder problem because it requires combining transaction history with state reconstruction at an arbitrary point, which is why the two launches are separated by months despite sharing the same infrastructure foundation.

Practical Impact for Builders

The balance-at endpoint removes a category of infrastructure that Solana application developers previously had to build and maintain themselves. Tax and accounting tools need precise cost basis at acquisition time; governance systems require provable token holdings at snapshot dates; airdrop eligibility checkers depend on wallet state at specific blocks. PnL calculators need entry and exit balances. All of these either required custom indexing or couldn't be built reliably at all.

Before this endpoint, teams building these features either ran their own full archival nodes (expensive, operationally complex), approximated via transaction replays (error-prone, slow), or skipped the feature entirely. A single API call now returns a verifiable, anchor-signed balance for any wallet and any token since genesis.

The endpoint is in beta, meaning response formats may change. Helius documentation and the current beta status are available at the Wallet API overview.