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Comparison · 2 models · Updated Nov 2, 2026

Inkling Small vs GPT-5.1 Codex mini

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

  1. 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

  2. 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

  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 SmallInkling Small: Text, Images, Audio · GPT-5.1 Codex mini: Text, Images
  • Self-hostingInkling SmallPublishes downloadable weights (Apache-2.0)
How the score is built
MeasureWeightInkling SmallGPT-5.1 Codex mini
Price50%5255
Inputs & features30%7060
Context window20%6144
Overall100%59/10054/100

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.

Inkling Small vs GPT-5.1 Codex mini specifications side by side
SpecificationInkling SmallThinking MachinesGPT-5.1 Codex miniOpenAI
Capability
Capabilities Index (ECI)150.5—
ECI rank#58 of 165—
GPQA DiamondGraduate-level science questions88.5%—
FrontierMath Tiers 1–3Research-level mathematics46.3%—
OTIS Mock AIME 2024–2025Competition mathematics90.0%—
SimpleQA VerifiedShort factual questions19.1%—
Price per million tokens
Input$0.58$0.25 (best)
Output$1.44 (best)$2.00
Cached input$0.116—
Blended (3:1)$0.795$0.688 (best)
Long-context rateSame rateSame rate
Price sourceOfficial Thinking Machines APIMedian of 16 providers
Limits
Context window1,048,576 tokens (best)400,000 tokens
Max output1,048,576 tokens (best)128,000 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsNoNo
AudioYesNo
VideoNoNo
ReasoningYeslow · medium · high · xhigh · maxYes
Tool callingYesYes
Structured outputNoNo
Availability
WeightsOpenApache-2.0Proprietary
API model IDthinkingmachines/Inkling-Small—
API providers1216 (best)
ReleasedJul 30, 2026Nov 13, 2025
Knowledge cutoff—Sep 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.

  • Inkling Small$8.68
  • GPT-5.1 Codex mini$6.50
04 — Questions

Which should you choose?

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

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, Inkling Small or GPT-5.1 Codex mini?

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. Inkling Small has an ECI of 150.5 and GPT-5.1 Codex mini has not been scored yet.

Which is better for coding?

There are no published SWE-bench Verified results for Inkling Small and GPT-5.1 Codex mini 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: Inkling Small up to 1,048,576, GPT-5.1 Codex mini up to 128,000 tokens.

Which can read images, PDFs, audio or video?

Inkling Small accepts text, images and audio; GPT-5.1 Codex mini accepts text and images. 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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