Model

AI21 Jurassic-2 (Ultra)

CLOSED

AI21's 2023 flagship API model (renamed from Jumbo) with zero-shot instruction-following and multilingual support; now Legacy on Bedrock.

ReasoningCodingVisionFunction callingTool useAgentic

51.9

Elo · rank #396

Parameters

Undisclosed

Active params

—

Context

8K tokens

Architecture

Dense Transformer (architecture undisclosed)

License

Proprietary

Languages

API price (in/out)

$18.8 / $18.8

Modalities

text

Benchmark results

Bar shows position within the tracked field; marker = field best

GSM8KMath22.5%#163

best: Llama 3.1 405B · 96.8%

HellaSwagReasoning78.8%#89

best: Claude 3 Opus · 95.4%

MMLUKnowledge48.0%#237

best: OpenAI o3 · 92.9%

OpenBookQAReasoning55.8%#20

best: Claude 1 · 90.8%

TruthfulQAKnowledge43.7%#69

best: Phi-3.5-MoE (16x3.8B, 6.6B active) · 77.5%

Run it locally

Closed weights — available via API only. No local deployment.

Input / M tok

$18.8

Output / M tok

$18.8

AI21 Jurassic family

Elo progression across releases

Resources

API price $18.8/$18.8 · each benchmark row carries its own source badge (see methodology)