Cost per coding-agent request

Is Devstral 2 or GPT-5.5 cheaper for coding agents?

For coding agents, GPT-5.5 costs 13x as much as Devstral 2 per request ($0.13 vs $0.010 on our measured traffic), because GPT-5.5 lists at $5 input, $0.50 cached input and $30 output per million tokens against $0.40, $0.04 and $2 for Devstral 2, and GPT-5.5 charges more for prompts over 272K tokens.

List prices: OpenRouter (vendor endpoint), OpenAI API pricing, checked 2026-10-13. Request costs: Standard Compute gateway data, 79,301 coding-agent requests from 75 users, Sep 13 to Oct 12, 2026. How we compute this

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Cost per coding-agent request, side by side

Cost at list price	Devstral 2	GPT-5.5
Prompt under 100K tokens50% of requests, 87% of input cached	$0.0062	$0.081
Prompt of 100K to 272K39% of requests, 88% of input cached	$0.015	$0.19
Prompt over 272K tokens11% of requests, 86% of input cached	n/a	n/a
Average request	$0.010	$0.13
100 requests	$1.01	$12.98
Median session16 requests; a session ends after 10 idle minutes	$0.12	$1.57
A month of regular usemedian of 20 users active on 5+ days	$12.73	$163

Each logged request priced at the vendor’s list rates for its own token counts, including cache reads and any higher rate for long prompts. Average output: 698 tokens per request. Both models are priced on the requests up to 262K tokens that fit in both context windows; band shares above describe all requests.

Benchmarks, speed and latency, side by side

Artificial Analysis	Devstral 2	GPT-5.5
Intelligence Index10 evaluations, 0 to 100	9	38
Terminal-Bench 4.0agentic coding in a terminal	0.0%	14.6%
Output speedmedian	n/a	105 tokens/s
Time to first answer tokenincludes thinking time	n/a	71 s

Source: Artificial Analysis (artificialanalysis.ai). Measured variants: Devstral 2; GPT-5.5 (Xhigh), speed on OpenAI. Fetched October 13, 2026. Artificial Analysis runs Terminal-Bench 4.0 in its own setup, so its scores differ from the tbench.ai leaderboard.

What to watch for

Devstral 2's 262K window cannot take 12% of coding-agent requests, so the comparison uses only requests both can take. GPT-5.5 is superseded: GPT-6.1 Sol costs $0.067 per request. GPT-5.5 scores clearly higher on the benchmarks above, so it may finish hard tasks in fewer steps.

FAQ

Is Devstral 2 cheaper than GPT-5.5 for coding agents?

Yes, at list prices. 100 average coding-agent requests cost $1.01 on Devstral 2 and $12.98 on GPT-5.5. A median 16-request session costs $0.12 vs $1.57. Measured on 79,301 real coding-agent requests (Sep 13 to Oct 12, 2026), counting only the requests up to 262K tokens that both can take.

How much does a month of GPT-5.5 vs Devstral 2 cost?

For the median regular user in our data (1,478 requests in 30 days), about $163 on GPT-5.5 and $12.73 on Devstral 2 at list price. Heavier users pay proportionally more.

Devstral 2 vs GPT-5.5: which is better for agents?

GPT-5.5 scores higher on output quality (7.6/10 vs 3.3/10), while Devstral 2 is the cheaper option. Devstral 2 is best for coding agents that need a Mistral open-weight model; GPT-5.5 is best for existing GPT-5.5 setups on an API key until they move to GPT-6.1 Sol. Live community votes on this page show what people actually prefer.

Can I switch between Devstral 2 and GPT-5.5 in the same agent?

Yes. Model-agnostic agents (Cline, Aider, OpenClaw, Hermes Agent, Kilo Code, OpenCode, Continue) let you swap models per task. Many people route hard tasks to the stronger model and routine work to the cheaper one.