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Notes from inside the machine.
How things work once they are in production: Solana execution, trading infrastructure, smart contracts. Written by the person who runs them.
- 6 min readRead →
How full is a Solana block? About a quarter. The limit you hit is the account
At 200 ms slots a Solana block may hold 50 million compute units and any one writable account 20 million. In 80 mainnet blocks I read on October 20, 2026, the median block consumed about 11 million, a quarter of the limit, but one block reached 45.3 million and one account inside it 18.7 million, 93% of its own limit. Why the account limit is the one that stops trades, and what a priority fee can do about it.
Solana · Compute Units · Priority Fees · Trading Bots
- 6 min readRead →
How many compute units does a Solana token transfer use? 76 on SPL Token, about 1,900 on Token-2022
Since the optimized token program (p-token) replaced SPL Token in May 2026, a transfer uses 76 compute units, down from 4,645. Token-2022 did not change: in 27,830 mainnet transactions I read on October 17, 2026, its transfers used 1,879 compute units and opening an account about ten times what SPL Token needs. What that means for compute limits and priority fees.
Solana · Compute Units · Token-2022 · Priority Fees · Trading Bots
- 7 min readRead →
Solana sBPFv3: why your next program deploy will fail unless you rebuild
With Agave 4.4, expected in November 2026, Solana accepts only sBPFv3 for new program deployments and upgrades (SIMD-0500). Programs already on chain keep running, but the next upgrade of any v0, v1 or v2 build is rejected. None of 20 major mainnet programs I checked on October 16 was v3 yet. How to check your build, what to rebuild with, and a deploy checker.
Solana · sBPF · Smart Contracts · Anchor
- 7 min readRead →
Solana durable nonces are being removed: how offline signing works next
Solana plans to remove durable nonces, the runtime feature that lets a signed transaction wait forever. The replacement is an on-chain signer program: the cold key signs a message with no blockhash, a hot fee payer sends it, and the program acts for the key through a PDA. Removal comes about six months after the replacement is ready, with no date yet. How it works, who is affected, and what to move now.
Solana · Durable Nonce · Offline Signing · Wallets
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Solana Alpenglow on October 21: what changes for bots, RPC and indexers
Alpenglow replaces TowerBFT on Solana mainnet at epoch 1064 on October 21, 2026. Finality goes from about 12.8 seconds to a target of about 150 ms, confirmed and finalized become the same state, votes leave blocks, and gRPC updates gain a bank_id. A timeline of the switch, a Votor playground, and the changes to make in code.
Solana · Alpenglow · Consensus · gRPC · Trading Bots
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Solana v1 transactions: 4,096 bytes, no lookup tables, and a priority fee that moved
Solana transaction v1 has been live on mainnet since September 15, 2026. It raises the size limit from 1,232 to 4,096 bytes, lists every account inline, and moves compute limits and the priority fee out of instructions into the message. How to detect it, what it breaks in RPC clients and parsers, and a fee converter.
Solana · Transactions · Priority Fees · Trading Bots
- 6 min readRead →
Solana rent in 2026: what an account costs now, and how to get the difference back
Solana is cutting the rent-exempt deposit by 90% in five steps. Two are live: on October 11, 2026 mainnet charges 5,080 lamports per byte, so a token account costs 0.00148844 SOL, down from 0.00203928. The formula, a cost playground, how older accounts take the extra back, and the constants to remove from your code.
Solana · Rent · Token Accounts · Infrastructure
- 8 min readRead →
Pump.fun October 2026 update: v3 trades, fee sweeps, negative virtual reserves and synthetic migration
Pump documented six changes on October 8, 2026: smaller buy_v3 and sell_v3 trades, fees that wait on the curve and pool until swept, the reason virtual_quote_reserves goes negative, a last buy with no max size, multi_hop_swap, and pump coins as quote mints. What each one is, with two playgrounds, and what a bot or indexer has to change.
Pump.fun · PumpSwap · Solana · Trading Bots
- 9 min readRead →
How long is a Solana slot now? 200 ms on paper, and what the chain really does
A Solana slot targets 200 ms from October 9, 2026, down from 400 ms in four steps since August. Real slots have run 16 to 19 ms longer than each target: I measured 267 ms during the 250 ms step. A slot clock to play with, a slots-to-time converter, and the numbers in a bot that changed.
Solana · Slot Time · Trading Bots · Infrastructure
- 9 min readRead →
How a Solana transaction actually lands: leaders, shreds, gRPC and Jito
A practitioner walkthrough of the path a Solana transaction takes from your bot to finality: RPC forwarding, the leader TPU, shreds over Turbine, Geyser gRPC, Jito bundles, and what really improves landing rate.
Solana · Trading Bots · gRPC · Jito · Infrastructure
- 6 min readRead →
Why you should never store private keys in .env files
A .env file keeps your private key in plain text where git, dependencies and backups can reach it. How to move it into Foundry's password-encrypted keystore with cast wallet import, with a steppable diagram of what changes.
Foundry · Security · Private Keys · Keystore
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assert vs require in Solidity: which one to use, and what each failure means
require validates what callers send. assert states what your own code guarantees. A steppable diagram of one call passing through both, the error each one produces, and how gas behaves since Solidity 0.8.0.
Solidity · Error Handling · Smart Contracts
- 7 min readRead →
ERC-20 approval frontrunning: how a changed allowance gets spent twice
When you change an ERC-20 allowance with approve, a spender watching the mempool can spend the old allowance first and the new one after. A steppable walkthrough of the race, why approve allows it, and the fixes that close it.
Solidity · ERC-20 · Security · Frontrunning
- 6 min readRead →
Slippage parameters in Solidity: what amountOutMin really protects
Slippage is the gap between the price you were quoted and the price your swap executes at. How amountOutMin and deadline turn a tolerance into an on-chain check, with a steppable diagram and the mistakes that leave a swap unprotected.
Solidity · DeFi · Slippage · DEX
- 5 min readRead →
receive vs fallback in Solidity: which one runs, and when
receive runs when a contract gets ether with empty calldata. fallback runs when the calldata matches no function, or when ether arrives and there is no receive. A steppable decision tree, the gas stipend, and the cases where neither runs.
Solidity · Ether Transfers · Smart Contracts