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leanstral-1-5Mistral AI

from /1M infreemistral ai sas
context262K33K out
best ttft1.51smistral ai sas
endpoints11 region
endpoints
1
regions
1
api
chat
released
May 2026
eu routing
available

capabilities 2/8

visionreasoningtoolscachingweb searchjson schemacomputer useimage gen

endpoints

1 / 1 region
Providers serving leanstral-1-5, with pricing and measured performance. Best value in each column is coloured.
#flags
1Mistral AI SASEU262Kfreefreefree1.51szdr
provider price, no markupper 1M tokensblank where no qualifying sample

measured

through Sep 12
median
1.24s3.31s5.37s07-0608-0309-072.00s
hover the plot for weekly values
time to first token per provider: current value, window low and high, and change across the window
providernowlowhighchange
Mistral AI SAS1.51s1.58s5.03s+6.3%

median wait before the first token lands. this is the number a user feels, and it moves with provider load through the day.

Lines are steps: each sample is one week of traffic held flat, not a slide from the week before. Click a name in the key to drop it from the plot. Measured through Sep 12.

benchmarks

artificial analysis
Benchmark scores, each normalised to 100
evalScore as a share of 100/100
MMLU Pro49.1
GPQA Diamond34.9
LiveCodeBench9.9
Intelligence Index5.5
Humanity's Last Exam3.5
5 evalsmean20.6

Scores from Artificial Analysis and public leaderboards, normalised to 100. Bar colour is the band, not the rank: green 80 and up, blue 55 and up, amber 30 and up. Benchmarks measure narrow skills, so test on your own workload before committing. Released 2023-12-11.

call it

model=
leanstral-1-5

requesty routes this id across every provider serving leanstral-1-5, picking on price and health and failing over automatically. the id stays valid when a provider changes underneath it

Base url is https://router.requesty.ai/v1 for every id here. One key reaches the whole catalog.

quickstart

openai compatible
main.py
from openai import OpenAI client = OpenAI(    api_key="YOUR_REQUESTY_API_KEY",    base_url="https://router.requesty.ai/v1",) response = client.chat.completions.create(    model="leanstral-1-5",    messages=[        {"role": "user", "content": "Explain quantum computing in one paragraph."},    ],) print(response.choices[0].message.content)

Change the base url, use your Requesty key, set the model to any id in the call pane. Existing OpenAI SDK code needs no other edit, and the same key reaches every other model in the catalog, so switching later is a one-parameter change. Browse all models

notes

reference

Leanstral 1.5 is an updated Lean 4 formal proof engineering model from Mistral AI, optimized for automated theorem proving and autoformalization. It has 119B total parameters with 6.5B active and supports a 256K token context window. It supports native function calling and structured output.

questions 6

Which providers serve leanstral-1-5?
leanstral-1-5 is available from 1 provider through Requesty: Mistral AI SAS. All endpoints share one OpenAI-compatible API and one key, and Requesty fails over between them automatically.
How much does leanstral-1-5 cost?
Pricing starts at free per million input tokens and free per million output tokens on the cheapest provider. Prices vary by provider and region; the table above shows every endpoint. Requesty charges exactly what the upstream provider charges, with no markup.
Is leanstral-1-5 open weights?
No. leanstral-1-5 is a proprietary model from Mistral AI, served through Mistral AI's own API and licensed cloud platforms.
What is the context window of leanstral-1-5?
leanstral-1-5 supports up to 262K tokens of context, with up to 33K output tokens per response. Some providers expose a smaller window; check the per-endpoint context column above.
How do I use leanstral-1-5 with the OpenAI SDK?
Install the OpenAI SDK, set base_url to "https://router.requesty.ai/v1", set your API key to your Requesty key, and set the model to "leanstral-1-5" or any endpoint id from the table above. The quickstart section shows Python, JavaScript and cURL snippets.
Should I call leanstral-1-5 by its managed id or a provider id?
Use the managed id, "leanstral-1-5". Requesty picks which of the 1 provider serves each request based on price and health, and fails over when one degrades, so the id keeps working while the routing changes underneath it. There is also an EU-only id, "leanstral-1-5@eu", which routes the same way but only through EU-hosted providers. Send a provider id like "mistral/leanstral-1-5" only when you need one specific deployment and want no failover.

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route leanstral-1-5 through one endpoint

One key for 1 provider on this model and 600+ others. No markup on provider prices, automatic failover, caching built in. Weekly aggregates in the measured pane come from production traffic routed through Requesty, one line per provider on a shared axis. Methodology

leanstral-1-51 provider1 endpointsfrom free /1M inctx 262Kttft 1.51supdated Sep 12