Grok 4.20 Beta1
SpaceXSI
Key facts · verified Oct 29, 2026
Grok 4.20 Beta1 is a SpaceXSI model. Its API price is $1.25 per million input tokens and $2.50 per million output tokens ($2.50 / $5.00 above 200K). Its context window is 1M tokens. It ranks #40 on LMArena's text leaderboard (Elo 1475, read 1 Nov 2026). Source: docs.x.ai.
Grok 4.20 Beta1 is a beta checkpoint of SpaceXSI's Grok 4.20 evaluated on LMArena. xAI's API serves Grok 4.20 as the GA models grok-4.20-0309-reasoning and grok-4.20-0309-non-reasoning. On LMArena's text leaderboard: 1475 Elo (rank 40).
Pricing & specs checkedSource: vendor documentation · checked Oct 29, 2026LMArena: 1475 Elo (rank 40) · source · retrieved Nov 1, 2026
Full Specifications
$1.25 / $2.50 per million tokens | |
|---|---|
| Identity | |
| Developer | SpaceXSI |
| Status | Beta checkpoint; superseded on the xAI API by GA grok-4.20-0309-reasoning and grok-4.20-0309-non-reasoning. |
| Licence | Proprietary |
| Self-hostable | No |
| Cost | |
| Blended $/1M tokensinput × 0.75 + output × 0.25 | $1.563 / 1M tokens |
| Input price | $1.250 / 1M tokens |
| Output price | $2.500 / 1M tokens |
| Capacity | |
| Context window | 1M tokens |
| Access | |
| API | Yes |
| Measured quality | |
| LMArena Elo | 1475 (checked Nov 2026) |
| LMArena rank | Rank 40 |
| Elo per dollarLMArena Elo ÷ blended $/1M tokens | 944 |