ZMIME
Comparison · 2 models · Updated Oct 4, 2026

GPT-5.1 Codex vs Jamba Large

GPT-5.1 Codex comes out ahead, 42 to 30 on our weighted score, and it is the cheaper option too.

  1. Our pick

    OpenAI

    GPT-5.1 Codex

    Released Nov 13, 2025

    42/100
    • ECI—
    • Price$1.25 / $10.00
    • Context400K
  2. AI21 Labs

    Jamba Large

    Released Jul 1, 2025

    30/100
    • ECI—
    • Price$2.00 / $8.00
    • Context256K
  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT-5.1 Codex is our pick

GPT-5.1 Codex is the better all-round choice, scoring 42/100 against Jamba Large (30). It leads on inputs & features and context window. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

  • CapabilityNot enough dataNo independent benchmark covers every model here yet
  • Lowest priceGPT-5.1 CodexGPT-5.1 Codex $3.44 · Jamba Large $3.50 per 1M tokens (3:1 blend)
  • Longest contextGPT-5.1 CodexGPT-5.1 Codex 400,000 · Jamba Large 256,000 tokens
  • Widest inputsGPT-5.1 CodexGPT-5.1 Codex: Text, Images · Jamba Large: Text
  • Self-hostingJamba LargePublishes downloadable weights
How the score is built
MeasureWeightGPT-5.1 CodexJamba Large
Price50%2424
Inputs & features30%7035
Context window20%4436
Overall100%42/10030/100

Left out because at least one model lacks the data: capability. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

GPT-5.1 Codex vs Jamba Large specifications side by side
SpecificationGPT-5.1 CodexOpenAIJamba LargeAI21 Labs
Capability
Capabilities Index (ECI)——
ECI rank——
Price per million tokens
Input$1.25 (best)$2.00
Output$10.00$8.00 (best)
Cached input——
Blended (3:1)$3.44 (best)$3.50
Long-context rateSame rateSame rate
Price sourceMedian of 10 providersOfficial AI21 Labs API
Limits
Context window400,000 tokens (best)256,000 tokens
Max output128,000 tokens (best)4,096 tokens
Inputs and features
TextYesYes
ImagesYesNo
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYesNo
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryOpen
API model ID—jamba-large
API providers10 (best)1
ReleasedNov 13, 2025Jul 1, 2025
Knowledge cutoffSep 30, 2024Aug 22, 2024
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • GPT-5.1 Codex$32.50
  • Jamba Large$36.00
04 — Questions

Which should you choose?

Which is better: GPT-5.1 Codex or Jamba Large?

GPT-5.1 Codex is the better all-round choice, scoring 42/100 against Jamba Large (30). It leads on inputs & features and context window. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

Which is cheaper, GPT-5.1 Codex or Jamba Large?

GPT-5.1 Codex is cheaper at $1.25 input / $10.00 output per million tokens (median across 10 API providers). Jamba Large costs $2.00 input / $8.00 output per million tokens (official AI21 Labs API price). At a typical mix of three input tokens to one output token, that is $3.44 per million tokens for GPT-5.1 Codex versus $3.50 for Jamba Large (1× as much).

Which scores higher on benchmarks?

There is no independent benchmark that covers both models yet. GPT-5.1 Codex has not been scored yet and Jamba Large has not been scored yet.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.1 Codex and Jamba Large yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.

Which has the bigger context window?

GPT-5.1 Codex has the largest context window at 400,000 tokens, against 256,000 for Jamba Large. Maximum output per response: GPT-5.1 Codex up to 128,000, Jamba Large up to 4,096 tokens.

Which can read images, PDFs, audio or video?

GPT-5.1 Codex accepts text and images; Jamba Large accepts text. GPT-5.1 Codex handles the widest range of inputs.

Are any of these open source?

Jamba Large publishes its weights and can be self-hosted; GPT-5.1 Codex is proprietary.

Which is newer?

GPT-5.1 Codex is the newest, released Nov 13, 2025. Jamba Large came out Jul 1, 2025. Knowledge cutoff: GPT-5.1 Codex Sep 30, 2024, Jamba Large Aug 22, 2024.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.