Data read October 27, 2026
Gradium TTS vs Smallest.ai Lightning v3.1: TTS API comparison
Speed cannot be compared: Coval does not measure Smallest.ai Lightning v3.1, so it has no P95 here.
On Artificial Analysis listener Elo, Gradium TTS is ahead (1,174 for Gradium TTS, 1,020 for Smallest.ai Lightning v3.1). List price per million characters: $36 to $57.80 for Gradium TTS, $17.50 to $25 for Smallest.ai Lightning v3.1.
Gradium TTS is ranked 1 of 23; Smallest.ai Lightning v3.1 is not in the multilingual speed ranking. Every comparison on this site uses Gradium TTS as its fixed reference, and no page says either model is better overall.
| Measure | Gradium TTS | Smallest.ai Lightning v3.1 | Ahead |
|---|---|---|---|
| Rank in the multilingual speed ranking | 1 | not ranked | n/a |
| Speed tier | Headroom | n/a | n/a |
| Median time to first audio (ms), lower is faster | 53.7 | n/a | n/a |
| P95 time to first audio (ms), lower is faster | 104.3 | n/a | n/a |
| Listener Elo (Artificial Analysis) | 1,174 | 1,020 | Gradium TTS |
| Customer-service Elo (Artificial Analysis) | 1,241 | 1,068 | Gradium TTS |
| Naturalness (Speko) | 1,592 | 1,544 | Gradium TTS |
| Naturalness estimate (Cekura, 1 to 5) | 4.51 | 4.49 | Gradium TTS |
| Reading accuracy (Cekura) | 79.5% | 81.3% | Smallest.ai Lightning v3.1 |
| Hard passages judged correct (Artificial Analysis) | n/a | n/a | n/a |
| Lowest list price per 1M characters (lower is cheaper) | $36 to $57.80 | $17.50 to $25 | Smallest.ai Lightning v3.1 |
| Languages tested (Artificial Analysis, Speko) | 4 | 4 | Tie |
| Access | Proprietary | Proprietary | n/a |
| Streaming status | Measured | Measured | n/a |
Ahead is computed from the figures only. A latency gap under 10 ms is a tie; listener Elo values whose 95% intervals overlap are a tie. A measure one benchmark does not hold is n/a for that model and is never estimated. See the methodology and each model page for sources.
Frequently asked questions
- Is Gradium TTS faster than Smallest.ai Lightning v3.1?
- Speed cannot be compared: Coval does not measure Smallest.ai Lightning v3.1, so it has no P95 here.
- How do Gradium TTS and Smallest.ai Lightning v3.1 compare on voice quality?
- On Artificial Analysis listener Elo, Gradium TTS is ahead (1,174 for Gradium TTS, 1,020 for Smallest.ai Lightning v3.1).
- Which is cheaper, Gradium TTS or Smallest.ai Lightning v3.1?
- List price per million characters: $36 to $57.80 for Gradium TTS, $17.50 to $25 for Smallest.ai Lightning v3.1.