Jamba 1.5 Large by AI21

Jamba 1.5 Large by AI21: model card

What it is

Jamba 1.5 Large is a model from AI21. On the Text Arena leaderboard at Arena.ai it ranks #297 of 421 models (snapshot taken 11 November 2026).

Leaderboard numbers

• Rank: #297 of 421
• Arena score: 1290
• Votes in pairwise comparisons: 8 662
• Price: $2 / $8 per 1M tokens (input / output) as listed on Arena
• Context window: 256K

Licence

Jamba Open

How to read these numbers

An Arena score comes from blind pairwise comparisons of answers, not from an absolute quality scale. A few points between neighbouring rows is often inside the error bars, so the top of a board is better read as ‘roughly one tier’ than as a strict order. Price and context are stated specs and do not feed the score. On the Agent Arena board the headline number is net improvement across real agent sessions, not an Elo-style score.

Source

• Text Arena leaderboard at Arena.ai
• Developer page: AI21