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OpenKey

MiniMax M2.5 vs GPT-5 Mini

MiniMaxOpenAIboth via one key, provider price + 3%

MiniMax M2.5 and GPT-5 Mini both target lightweight, high-throughput reasoning work, but they solve different problems. M2.5 is text-only, cheaper, and scores higher across every Design Arena category both models share. GPT-5 Mini accepts images and files, holds a larger context window, and carries OpenAI's tool-calling and structured-output stack. The choice comes down to whether your workload needs multimodal input and long context, or raw coding output at low cost.

Spec vs spec

SpecMiniMax M2.5GPT-5 Mini
Context window205K400K
Max output197K128K
Input modalitiestexttext, image, file
Output modalitiestexttext
Knowledge cutoffMay 31, 2024
ReleasedFeb 12, 2026Aug 7, 2025
Reasoningalways onalways on

Pricing

Per 1M tokens. Provider price plus the flat 3% fee — the sum is what you pay.

openkey.ai

minimax/minimax-m2.5

Input · 1M tokens

$0.120 + 3%$0.124

Output · 1M tokens

$0.480 + 3%$0.494

FEE — FLAT, EVERY MODEL3%

openkey.ai

openai/gpt-5-mini

Input · 1M tokens

$0.250 + 3%$0.258

Output · 1M tokens

$2.00 + 3%$2.06

Cache read · 1M tokens

$0.025 + 3%$0.026

FEE — FLAT, EVERY MODEL3%

One workload, priced on both

10M input + 2M output tokens at each model's price, flat 3% fee included.

minimax/minimax-m2.5Cheaper

$2.22

$2.16 provider + 3%

openai/gpt-5-mini

$6.70

$6.50 provider + 3%

Benchmarks

Design Arena categories where both models have results. Higher Elo and lower rank win.

MiniMax M2.5GPT-5 Mini
CategoryEloRankEloRank
3D1246#311114#73
Code1256#291164#64
Data viz1216#401167#62
Game dev1242#331194#54
SVG1208#261149#42
UI components1228#371161#57
Websites1265#261167#62

Head-to-head preference voting. How we filter and rank

Pricing math on a real workload

For 10M input tokens + 2M output tokens: MiniMax M2.5 costs $2.16 on OpenKey (provider price $0.12/M in, $0.48/M out, ×1.03 fee). GPT-5 Mini costs $6.50 for the same workload (provider price $0.25/M in, $2.00/M out, ×1.03 fee). That's a 3x cost gap in M2.5's favor, driven mostly by output pricing — GPT-5 Mini's completion tokens run at $2.06/M on OpenKey versus M2.5's $0.4944/M, a ratio the computed input_price_ratio (0.48) doesn't even capture since output is the bigger driver here. If your app generates a lot of tokens (long code files, long responses), this gap compounds fast. GPT-5 Mini does offer cache reads at $0.025/M provider price, which M2.5 doesn't list — worth checking if you're doing repeated-context calls.

Coding and frontend benchmarks

On Design Arena, M2.5 outranks GPT-5 Mini in every category both models report. Codecategories: M2.5 at elo 1256 (rank 29) vs GPT-5 Mini at elo 1164 (rank 64). Website: M2.5 at elo 1265 (rank 26) vs GPT-5 Mini at elo 1167 (rank 62). Dataviz: 1216 (rank 40) vs 1167 (rank 62). Gamedev: 1242 (rank 33) vs 1194 (rank 54). SVG: 1208 (rank 26) vs 1149 (rank 42). UI components: 1228 (rank 37) vs 1161 (rank 57). 3D: 1246 (rank 31) vs 1114 (rank 73). If your use case is generating or evaluating code, UI, or visual output, M2.5's rank advantage is consistent, not a one-off.

Context and modality differences

GPT-5 Mini's context window is 400,000 tokens against M2.5's 204,800 — roughly double, matching the computed context_ratio of 0.51. GPT-5 Mini also accepts image and file inputs alongside text; M2.5 is text-only in and out. M2.5's max output is larger at 196,608 tokens versus GPT-5 Mini's 128,000, so if you need very long generated responses (not long inputs), M2.5 has more room. Pick based on which end of the pipe is bottlenecked: long documents and images push you to GPT-5 Mini, long generated output pushes you to M2.5.

Reasoning controls and tooling

Both models require reasoning (mandatory: true) — there's no way to disable it on either. GPT-5 Mini exposes four effort levels (high, medium, low, minimal) with medium as default, giving you a lever to trade latency for quality. M2.5 exposes a reasoning_effort parameter too, plus a much longer list of supported parameters overall — including logit_bias, logprobs, top_k, top_logprobs, and min_p, none of which GPT-5 Mini's parameter list includes. If you're doing fine-grained sampling control or logprob-based evaluation, M2.5's parameter surface is wider.

Which model for which job

Use casePickWhy
Code generation / coding agentsMiniMax M2.5Higher elo across every Design Arena code and web category (e.g. codecategories 1256 vs 1164)
High-volume, cost-sensitive pipelinesMiniMax M2.5$2.16 vs $6.50 on a 10M-in/2M-out workload
Document or image analysisGPT-5 MiniOnly GPT-5 Mini accepts image and file inputs; M2.5 is text-only
Long-input tasks (large codebases, long docs)GPT-5 Mini400,000 token context vs 204,800 for M2.5
Long-output generation (large files, reports)MiniMax M2.5196,608 max output tokens vs 128,000 for GPT-5 Mini
Fine-grained sampling / logprob analysisMiniMax M2.5Supports logprobs, top_logprobs, top_k, min_p — not in GPT-5 Mini's parameter list

Questions

Which is cheaper, MiniMax M2.5 or GPT-5 Mini?
MiniMax M2.5, by a wide margin. On OpenKey, a 10M input / 2M output workload costs $2.16 with M2.5 versus $6.50 with GPT-5 Mini — roughly 3x. M2.5's provider price is $0.12/M input and $0.48/M output; GPT-5 Mini's is $0.25/M input and $2.00/M output, before the flat 3% fee.
Does either model support images?
Only GPT-5 Mini. Its input modalities are text, image, and file. MiniMax M2.5 is text-only on both input and output. If your workload involves screenshots, PDFs, or scanned documents, GPT-5 Mini is the only option of the two.
Which has the bigger context window?
GPT-5 Mini, at 400,000 tokens versus 204,800 for MiniMax M2.5 — roughly double, matching the computed context ratio of 0.51. M2.5 counters with a larger max output ceiling of 196,608 tokens against GPT-5 Mini's 128,000.
Which model scores better on coding benchmarks?
MiniMax M2.5, on every shared Design Arena category. In codecategories it scores elo 1256 (rank 29) versus GPT-5 Mini's 1164 (rank 64); in website generation, 1265 (rank 26) versus 1167 (rank 62). Both models are available through OpenKey with one key and a flat 3% fee on provider pricing.

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