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Timely Vote Credits (TVC) is the SIMD-0123 credit-weighting mechanism on Solana that scales each successfully landed validator vote between 1 and 16 credits according to how quickly the vote lands relative to the slot it confirms, replacing the prior all-or-nothing model where every landed vote earned exactly 1 credit regardless of latency. Vote credits weight a validator's share of per-epoch inflation rewards, so TVC turns voting latency — not just liveness — into a direct yield input.

The mechanism was specified in SIMD-0123 and activated on mainnet in 2024. It is unrelated to the Alpenglow upgrade (SIMD-0326, see the Alpenglow entry) — TVC continues to operate today and will remain operative under Alpenglow's vote aggregation path.

How the credit scale works

Under TVC, when a validator votes on slot N and that vote is included by the leader of slot N+k, the credit value is determined by k:

  • k = 1 — vote lands in the immediately following block, earning the maximum 16 credits.
  • Credit value decays as k grows, stepping down through the integer range toward 1 credit at the eligibility boundary.
  • Votes that land past the eligibility window (typically k > ~32 slots, per the SIMD-0123 specification) earn 0 credits, identical to a dropped vote.

The replacement of the binary 0-or-1 credit model with a 1-to-16 latency-weighted scale is the entire substance of TVC. Skip rate, commission, and stake delegation paths are unchanged.

Why two validators with identical skip rates diverge on credits

Skip rate measures leader-side block production — the percentage of a validator's assigned leader slots in which it failed to produce a confirmed block (see the skip rate entry). TVC measures voter-side performance: how fast the validator's vote on someone else's block lands in the next leader's TPU. A validator is in voter mode for the overwhelming majority of slots, since it is leader for only ~1/N of slots weighted by stake share.

Two validators each posting a 0.05% 30-day skip rate can therefore record meaningfully different TVC credit ratios:

  • Geographic placement. A validator co-located in a low-latency region near where most stake currently sits (Frankfurt, Amsterdam, Ashburn) lands votes at lower k than one a transcontinental hop further from the active leader population. The same vote-submission timing translates to different credit values purely because of route-distance to the next leader.
  • Peering and gossip path. Direct peering to high-stake validators reduces hop count; poor peering or default gossip routing adds slots of latency.
  • Local node tuning. Vote-transaction construction and submission timing inside the node — TPU client choice, vote signing latency, transaction-forwarding behavior — varies between Agave, Jito-Solana, and Frankendancer (see the Firedancer entry) and across operator configurations.

Stakewiz exposes the resulting figure as the credit_ratio field at api.stakewiz.com/validators — normalized against the cluster's best-performing validator over the trailing window. A credit_ratio of 0.98 means the validator captured 98% of the credits a perfect-latency validator earned over the same number of assigned vote slots.

SFDP and Wiz Score interpretation

The Solana Foundation Delegation Program sets a TVC-aware performance bar: participating validators must keep their vote credits at or above 97% of the cluster average per epoch, per solana.org/delegation-criteria. A validator can sit well within the skip-rate threshold (network average + 5 percentage points) and still fail the credit-ratio threshold purely on voting latency.

The Wiz Score folds vote-credit performance into its composite ranking under the "vote success" component. Stakewiz's documentation describes this input as TVC-aware — the score reflects credit ratios captured under the 1-to-16 scale, not the legacy binary vote-success metric. Cite credit ratios alongside skip rate when comparing operators; skip rate alone is an incomplete picture of validator performance under TVC.

Terminology traps

  • "Vote success rate" in pre-TVC tooling refers to the percentage of submitted votes that landed at all (the binary metric). Verify whether a source's "vote success" number is the pre-TVC binary value or the post-TVC credit ratio before comparing — they are not directly comparable.
  • TVC is not the same as Alpenglow. TVC is live today on the current consensus protocol. Alpenglow (SIMD-0326) replaces per-slot vote transactions entirely with the Validator Admission Ticket model; vote aggregation under Alpenglow's Votor component still produces credit-weighted rewards, but the on-chain vote-transaction stream that TVC currently meters will be gone.
  • Credit ratio alone does not determine staker yield. Inflation rewards are credit ratio × active stake × commission residual. A validator with a 0.99 credit ratio and 50% commission delivers less staker yield than one with a 0.96 ratio and 0% commission, despite the latency advantage of the first.

Sources

TVC credit ratios cited reference Stakewiz cluster data at epoch 971, 2026-05-15. The 1-to-16 scale is protocol-level and stable since SIMD-0123 activation; per-validator credit ratios fluctuate each epoch with network conditions.