Solana glossary

Plain-language definitions of the terms that come up around Solana RPC and high-frequency trading infrastructure. Built by the team running the nodes.

Commitment level

How settled a piece of Solana state is when you read it. The levels, from least to most certain, are processed (a validator executed it), confirmed (a supermajority voted), and finalized (rooted and irreversible). Lower levels are faster but more provisional. Learn more →

Co-location

Running your infrastructure physically close to Solana stake clusters and the Jito Block Engine, in the same datacenters, to minimize network hops and distance. Proximity is the cheapest latency there is, and the foundation of low-latency reads and transaction landing. Learn more →

Decoded shreds

Transactions reconstructed and decoded straight from the shred propagation layer, before any block is assembled. They give a first-seen, pre-confirmation view of the network - the earliest moment a transaction is observable. Learn more →

Dedicated node

A private, single-tenant Solana node provisioned to your specs on bare metal, rather than shared multi-tenant infrastructure. No noisy neighbors means deterministic tail latency and jitter. Learn more →

First-seen

The earliest moment you can observe a transaction - while its block is still propagating as shreds, before any validator has rolled it into a confirmed block. It sits below the processed commitment and is the prize that latency-sensitive strategies chase. Learn more →

Geyser

Solana's plugin interface that lets account, transaction, slot, and block data flow out of a validator the moment it is processed. Yellowstone is the widely-used gRPC implementation of the Geyser interface. Learn more →

gRPC

A high-performance, streaming RPC protocol. On Solana, Geyser-based gRPC (Yellowstone) pushes live updates to you over one long-lived stream with server-side filters, instead of you repeatedly polling a JSON-RPC endpoint. Learn more →

Jito Block Engine

Infrastructure that runs an auction for bundles of transactions on Solana. Searchers submit bundles with a tip, and the highest-tipping bundles win inclusion and ordering. It is the mechanism behind competitive MEV on Solana. Learn more →

Jito bundle

A set of transactions that execute all-or-nothing, in a specific order, submitted to the Jito Block Engine with a tip. Used when you need atomicity, guaranteed ordering, or to bid for inclusion. Learn more →

Leader

The validator responsible for producing the block for a given slot. The leader schedule is known for the whole epoch in advance, so you can send transactions directly to the current and upcoming leaders instead of broadcasting and hoping. Learn more →

MEV

Maximal Extractable Value - the profit a participant can capture by influencing the inclusion and ordering of transactions in a block (for example, arbitrage or liquidations). On Solana, MEV is largely contested through the Jito Block Engine.

Priority fee

A compute-unit price you attach to a transaction. When a leader has more transactions than it can fit, it orders them by priority fee, so a higher fee raises your place in line. It improves odds but does not guarantee inclusion. Learn more →

QUIC

The UDP-based transport protocol Solana validators use to accept transactions at the TPU. Sending directly to leaders over QUIC removes RPC-forwarding hops.

RPC (JSON-RPC)

Remote Procedure Call - the request/response API you use to read Solana state and submit transactions over HTTP, plus WebSocket subscriptions. It is the workhorse for reads, writes, and history. Learn more →

Shred

The smallest unit of a Solana block - a network-sized, erasure-coded packet of block data. Leaders split blocks into shreds and propagate them across the cluster through Turbine, so reading shreds lets you see transactions while a block is still in flight. Learn more →

Slot

A roughly 400-millisecond window in which a designated leader can produce a block. Solana time is measured in slots, and where you read inside a slot (shred-time vs block-time) decides how early you see state.

Stake-weighted QoS (SWQoS)

A mechanism that prioritizes transactions arriving over connections backed by stake. During congestion, staked connections get preferential access to a leader, which improves landing rate when the network is saturated. Learn more →

TPU

Transaction Processing Unit - the ingress on the current leader that accepts transactions over QUIC. A purpose-built sender delivers straight to the current and upcoming leaders' TPUs, skipping forwarding hops. Learn more →

Turbine

Solana's block propagation protocol, which fans shreds out across the validator set in a tree so a large block can reach the whole cluster quickly. It is how a block travels before it is fully assembled.

Yellowstone gRPC

The widely-used gRPC implementation of Solana's Geyser plugin interface. It streams accounts, transactions, and slots out of a validator in real time with rich server-side filters, scaling far better than fanning out WebSocket subscriptions. Learn more →