A little mimic. A lot of possibility.

Test data,
with character.

Typed fixtures. Coherent scenarios. Failures you can replay.

Give your tests a little life. Build fixtures that fit your schemas, keep related data connected, and bring a failing case back on cue.

Meet Mimlet Explore the source

Published alpha · 0.1.0-alpha.2
Available on npm’s next channel.

your-next-test.tsTS

ts

import Type from 'typebox';
import { fluent } from '@mimlet/core';
import { fromTypeBox } from '@mimlet/typebox';

const User = Type.Object({
  id: Type.String({ default: 'user-1' }),
  role: Type.Union([
    Type.Literal('reader'),
    Type.Literal('admin'),
  ]),
});

const users = fluent(fromTypeBox(User), ['id', 'role']);
export const admin = users.withRole('admin').buildValidated();

{ id: 'user-1', role: 'admin' }validated

At home with your schemas

TypeBox
Zod
Valibot
ArkType
Effect
JSON Schema

See each integration’s capabilities

Small fixtures. Bigger stories.

Make the data part
the easy part.

From one object to a whole test world, keep the pieces you care about under your control.

01 /

Your schema. Its natural habitat.

Keep your native types, validation and codecs. Start with a supported generator, or bring a factory for the details only you know.

Find your adapter

02 /

A whole world, connected.

A customer, their order, the right total. Describe the relationships once, then build a coherent scenario for the test in front of you.

Build a scenario

03 /

That failure? Bring it back.

Use explicit seeds and compatible replay records to reproduce a run. Shrink the inputs and recompute the relationships as the case gets smaller.

Meet replay and shrinking

Bring just what you need

A small core.
Room to grow.

The builder core has no runtime dependencies. Add generation, protocols, property testing, or a local playground when the job calls for them.

@mimlet/core the core@mimlet/typebox@mimlet/zod@mimlet/arktype@mimlet/fast-check@mimlet/graphql@mimlet/codegenhey-api-buildersExplore all 19 packages

For coding agents, too

Good context.
Better fixtures.

Give your coding agent a clear starting point: real APIs, working recipes, and the boundaries that matter.

Open the agent guide

Less API guesswork

Typed builders and tested recipes make the intended operations explicit.

More repeatable debugging

Save a compatible replay record and return to the failing case.

A clear path through the docs

Read concise Markdown, choose an adapter, and know when to use a factory.