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Understudy Labs

Effortlessly move to open weight models

An open-source toolkit to capture traces, evaluate cheaper models against benchmarks, and ship specialist routes you own. Capture traces from LLM production workflows with a single install that deploys within coding agents you already use. Hosted infrastructure is optional. Evaluate the captured traces and set a benchmark for success. Every future model switch meets or exceeds it in A/B testing. Train and fine-tune a new model on prompts and weights you always own. Start locally and scale into cloud-hosted processes as you see success. Deploy a new model only when the held-out eval is beaten. Serve it wherever you want. Production data feeds back into training and compounds performance over time. Test. Learn. Deploy. Repeat.
Active Founders
Luis Manrique
Luis Manrique
Founder
Founder at Understudy Labs (YC S26). Previously founding Member of Technical Staff (and founding sales guy) at Gumloop, closing ~$2M in first year. Led Ads ML and also consumer AI as first PM at Instacart's Carrot AI. Prior co-founder/CEO at Ones and Zeros (text-to-SQL using transformers). Early at Wildfire (acquired by Google), then 5 years across Google's ads ML and programmatic platforms. SVP Solutions at VideoAmp building TV measurement infrastructure.
Aamir Poonawalla
Aamir Poonawalla
CTO & Co-Founder
Founder at Understudy Labs (YC S26). 9 years at Instacart. Built the ads serving and ML infrastructure, auction platform, and experimentation framework. 2nd time YC Founder. MS in Computer Science from Georgia Tech.
Company Launches
Understudy: The self-optimizing inference cloud
See original launch post

Hey YC! We’re Luis and Aamir, founders of Understudy.

TL;DR

We help you cut your company’s Anthropic bill by 80% with no loss of performance.

Understudy is an inference cloud. We capture your employee’s AI work traces, train smaller models, and automatically deploy them (only when they outperform the expensive model you are currently paying for).

Instead of renting the same frontier model forever, your AI infrastructure gets cheaper and better every time it runs.

See more: https://youtu.be/YhfoOchpYaw

The problem

Last week, we met with a company spending $40M/year on Anthropic. And it’s only going in one direction.

To them, it feels totally out of control.

They’re not alone - every company we meet is spending record amounts on models from frontier labs.

But almost none of that spending compounds.

I.e. You send a prompt, pay for the answer, and throw away the experience. Six months later, you are still renting the same general-purpose model at roughly the same price.

Meanwhile, training custom models requires an entire ML team to collect and clean traces, build evals, choose training data, fine-tune and reinforce models, test serving configurations, compare cost, latency, and quality, safely deploy or roll back the winner.

For most companies, it’s just too much to bother with.

What Understudy does

Point Understudy at an AI workload.

We capture how your existing agent performs, turn those traces into evals, and start training smaller models that can do the same job better.

Understudy handles the entire loop:

Observe → evaluate → train → test → deploy → repeat

A new model is promoted only when it beats the incumbent on the metrics you care about, such as:

  • task success
  • inference cost
  • latency
  • privacy
  • deployment size

Your customized models are owned by you, and can run in our cloud, your cloud, or on-premise.

An example

Suppose your product uses Claude for a repetitive legal workflow.

Understudy observes successful production runs, learns the specific tools and judgment required for that workflow, and trains a specialized open-weight model.

Once that model matches or beats Claude on a held-out evaluation, Understudy starts routing production traffic to it.

As more work is completed, the model keeps improving.

Why us

Aamir and I met building Instacart’s optimization and experimentation systems, growing multiple business lines to more than $1B in annual revenue.

We started Understudy because we believe every company using AI should be accumulating intelligence, not accumulating API bills.

Our ask

Spending too much on repetitive model workloads? Ready to own your own models? We want to meet you - come to understudylabs.com today.

YC Summer 2026 Application Video
Understudy Labs
Founded:2026
Batch:Summer 2026
Team Size:2
Status:
Active
Location:San Francisco
Primary Partner:Tyler Bosmeny