A guide to user-in-the-loop product and marketing

Learn how to use simulated users to test and validate your work while it is still in progress. See how to run simulations for problem discovery, concept testing, feature prioritisation, headline and messaging tests, conversion, and findability. Fix problems while they're cheap, not after launch.

Accuracy

The predictions in these lessons were all generated by state-of-the-art Anacreon models. Anacreon predicts how individuals answer new questions, tested against data from real people.

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0.775

Ordinal alignment (industry standard)

User in the loop 11 min

Introduction to user-in-the-loop

The basics end to end. Planning simulations, running them, synthesising the results, applying the findings to version two, and planning the next round.

Start here

Ask them

Find out what actually annoys the people you're building for Agentic problem space search Coming soon

Pressure-test the idea while it's still a paragraph Idea expansion and simulation Coming soon

Discover which features users want before building them Predictive priority mapping Coming soon

Find a winning headline without the internal debate Testing a thousand headlines Coming soon

Find out why people pick your competitor Competitive preference modelling Coming soon

Find out how a change will land before you announce it Downside prediction and preemption Coming soon

Watch them

Watch people try to convert before you launch Measure conversion pre-launch Coming soon

See if people can find what you just built Compute user search paths Coming soon

Find out what people think you do Predictive comprehension Coming soon

Discover the dead ends people actually hit Interest-led simulated journeys Coming soon

Test it with users before it's live Scan for user problems on every push Coming soon

Where it runs

Simulate users without leaving your branch Claude Code Coming soon

Introduce your assistant to simulated users Claude Desktop / ChatGPT Coming soon

Create a decision agent with users in the loop MCP Coming soon

Wire user simulation into your own stack API Coming soon

Straight answers

How accurate is this, actually Research Coming soon

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Pricing

Free

49 free public answers-1 models

User research and user journey modes

The app, the MCP, and the API

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Custom

Get a custom model of your users

Semilattice Custom is a partnership, not a licence. We build a model of your users and meet regularly to help you simulate your decisions.

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$1,799 / month

Everything in Free, plus:

A custom anacreon model of your users

Organisation features with unlimited seats

Regular working sessions and support