← Text-to-Speech 
Smallest
lightning_v3.1_pro
Measured 2026-09-08
Run lightning_v3.1_pro on Speko →One API, every model on this board.
Naturalness
1447
Win % · 95% CI
—
Drift
—
not measured
Synth p50
—
not measured
Robustness
—
Not yet measured: the en-US NSW robustness battery has not been run on this model (row added 2026-09-08 with an auto-MOS naturalness estimate). Pending, not exempt.
Cost / 1M chars
$19.5
Pay-as-you-go; $0.195/10k chars (smallest.ai/pricing/models, corroborated by the model card).
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URL
https://benchmarks.speko.ai/tts/smallest-lightning-v3-1-pro