ZMIME
Comparison · 2 models · Updated Nov 2, 2026

GPT-5.1 Codex mini vs Inkling Small

Inkling Small comes out ahead, 59 to 54 on our weighted score, though GPT-5.1 Codex mini is 14% cheaper per token.

  1. OpenAI

    GPT-5.1 Codex mini

    Released Nov 13, 2025

    54/100
    • ECI—
    • Price$0.25 / $2.00
    • Context400K
    Full specs Remove GPT-5.1 Codex mini
  2. Our pick

    Thinking Machines

    Inkling Small

    Released Jul 30, 2026

    59/100
    • ECI150.5
    • Price$0.58 / $1.44
    • Context1.05M
    Full specs Remove Inkling Small

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Inkling Small is our pick

Inkling Small is the better all-round choice, scoring 59/100 against GPT-5.1 Codex mini (54). It leads on inputs & features and context window. GPT-5.1 Codex mini wins on price. 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 Codex miniGPT-5.1 Codex mini $0.688 · Inkling Small $0.795 per 1M tokens (3:1 blend)
  • Longest contextInkling SmallInkling Small 1,048,576 · GPT-5.1 Codex mini 400,000 tokens
  • Widest inputsInkling SmallGPT-5.1 Codex mini: Text, Images · Inkling Small: Text, Images, Audio
  • Self-hostingInkling SmallPublishes downloadable weights (Apache-2.0)
How the score is built
MeasureWeightGPT-5.1 Codex miniInkling Small
Price50%5552
Inputs & features30%6070
Context window20%4461
Overall100%54/10059/100

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 mini vs Inkling Small specifications side by side
SpecificationGPT-5.1 Codex miniOpenAIInkling SmallThinking Machines
Capability
Capabilities Index (ECI)—150.5
ECI rank—#58 of 165
GPQA DiamondGraduate-level science questions—88.5%
FrontierMath Tiers 1–3Research-level mathematics—46.3%
OTIS Mock AIME 2024–2025Competition mathematics—90.0%
SimpleQA VerifiedShort factual questions—19.1%
Price per million tokens
Input$0.25 (best)$0.58
Output$2.00$1.44 (best)
Cached input—$0.116
Blended (3:1)$0.688 (best)$0.795
Long-context rateSame rateSame rate
Price sourceMedian of 16 providersOfficial Thinking Machines API
Limits
Context window400,000 tokens1,048,576 tokens (best)
Max output128,000 tokens1,048,576 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsNoNo
AudioNoYes
VideoNoNo
ReasoningYesYeslow · medium · high · xhigh · max
Tool callingYesYes
Structured outputNoNo
Availability
WeightsProprietaryOpenApache-2.0
API model ID—thinkingmachines/Inkling-Small
API providers16 (best)12
ReleasedNov 13, 2025Jul 30, 2026
Knowledge cutoffSep 30, 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 mini$6.50
  • Inkling Small$8.68
04 — Questions

Which should you choose?

Which is better: GPT-5.1 Codex mini or Inkling Small?

Inkling Small is the better all-round choice, scoring 59/100 against GPT-5.1 Codex mini (54). It leads on inputs & features and context window. GPT-5.1 Codex mini wins on price. 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 mini or Inkling Small?

GPT-5.1 Codex mini is cheaper at $0.25 input / $2.00 output per million tokens (median across 16 API providers). Inkling Small costs $0.58 input / $1.44 output per million tokens (official Thinking Machines API price). At a typical mix of three input tokens to one output token, that is $0.688 per million tokens for GPT-5.1 Codex mini versus $0.795 for Inkling Small (1.2× as much).

Which scores higher on benchmarks?

There is no independent benchmark that covers both models yet. GPT-5.1 Codex mini has not been scored yet and Inkling Small has an ECI of 150.5.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.1 Codex mini and Inkling Small 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?

Inkling Small has the largest context window at 1,048,576 tokens, against 400,000 for GPT-5.1 Codex mini. Maximum output per response: GPT-5.1 Codex mini up to 128,000, Inkling Small up to 1,048,576 tokens.

Which can read images, PDFs, audio or video?

GPT-5.1 Codex mini accepts text and images; Inkling Small accepts text, images and audio. Inkling Small handles the widest range of inputs.

Are any of these open source?

Inkling Small publishes its weights (Apache-2.0) and can be self-hosted; GPT-5.1 Codex mini is proprietary.

Which is newer?

Inkling Small is the newest, released Jul 30, 2026. GPT-5.1 Codex mini came out Nov 13, 2025. Knowledge cutoff: GPT-5.1 Codex mini Sep 30, 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 Nov 2, 2026.

05 — Keep comparing

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