Form System Guide

This skill provides patterns for building forms using Sentry's new form system built on TanStack React Form and Zod validation.

Core Principle

• Always use the new form system (useScrapsForm, AutoSaveField) for new forms. Never create new forms with the legacy JsonForm or Reflux-based systems.

• All forms should be schema based. DO NOT create a form without schema validation.

Imports

All form components are exported from @sentry/scraps/form:

import {z} from 'zod';

import {
  AutoSaveField,
  defaultFormOptions,
  setFieldErrors,
  useScrapsForm,
} from '@sentry/scraps/form';

Important: DO NOT import from deeper paths, like '@sentry/scraps/form/field'. You can only use what is part of the PUBLIC interface in the index file in @sentry/scraps/form.

---

Form Hook: useScrapsForm

The main hook for creating forms with validation and submission handling.

Basic Usage

import {z} from 'zod';

import {defaultFormOptions, useScrapsForm} from '@sentry/scraps/form';

const schema = z.object({
  email: z.string().email('Invalid email'),
  name: z.string().min(2, 'Name must be at least 2 characters'),
});

function MyForm() {
  const form = useScrapsForm({
    ...defaultFormOptions,
    defaultValues: {
      email: '',
      name: '',
    },
    validators: {
      onDynamic: schema,
    },
    onSubmit: ({value, formApi}) => {
      // Handle submission
      console.log(value);
    },
  });

  return (
    <form.AppForm>
      <form.FormWrapper>
        <form.AppField name="email">
          {field => (
            <field.Layout.Stack label="Email" required>
              <field.Input value={field.state.value} onChange={field.handleChange} />
            </field.Layout.Stack>
          )}
        </form.AppField>

        <form.SubmitButton>Submit</form.SubmitButton>
      </form.FormWrapper>
    </form.AppForm>
  );
}

Important: Always spread defaultFormOptions first. It configures validation to run on submit initially, then on every change after the first submission. This is why validators are defined as onDynamic, and it's what provides a consistent UX.

Returned Properties

Property	Description
AppForm	Root wrapper component (provides form context)
FormWrapper	Form element wrapper (handles submit)
AppField	Field renderer component
FieldGroup	Section grouping with title
SubmitButton	Pre-wired submit button
Subscribe	Subscribe to form state changes
reset()	Reset form to default values
handleSubmit()	Manually trigger submission

---

Field Components

All fields are accessed via the field render prop and follow consistent patterns.

Input Field (Text)

<form.AppField name="firstName">
  {field => (
    <field.Layout.Stack label="First Name" required>
      <field.Input
        value={field.state.value}
        onChange={field.handleChange}
        placeholder="Enter your name"
      />
    </field.Layout.Stack>
  )}
</form.AppField>

Number Field

<form.AppField name="age">
  {field => (
    <field.Layout.Stack label="Age" required>
      <field.Number
        value={field.state.value}
        onChange={field.handleChange}
        min={0}
        max={120}
        step={1}
      />
    </field.Layout.Stack>
  )}
</form.AppField>

Select Field (Single)

<form.AppField name="country">
  {field => (
    <field.Layout.Stack label="Country">
      <field.Select
        value={field.state.value}
        onChange={field.handleChange}
        options={[
          {value: 'us', label: 'United States'},
          {value: 'uk', label: 'United Kingdom'},
        ]}
      />
    </field.Layout.Stack>
  )}
</form.AppField>

Select Field (Multiple)

<form.AppField name="tags">
  {field => (
    <field.Layout.Stack label="Tags">
      <field.Select
        multiple
        value={field.state.value}
        onChange={field.handleChange}
        options={[
          {value: 'bug', label: 'Bug'},
          {value: 'feature', label: 'Feature'},
        ]}
        clearable
      />
    </field.Layout.Stack>
  )}
</form.AppField>

Switch Field (Boolean)

<form.AppField name="notifications">
  {field => (
    <field.Layout.Stack label="Enable notifications">
      <field.Switch checked={field.state.value} onChange={field.handleChange} />
    </field.Layout.Stack>
  )}
</form.AppField>

TextArea Field

<form.AppField name="bio">
  {field => (
    <field.Layout.Stack label="Bio">
      <field.TextArea
        value={field.state.value}
        onChange={field.handleChange}
        rows={4}
        placeholder="Tell us about yourself"
      />
    </field.Layout.Stack>
  )}
</form.AppField>

Range Field (Slider)

<form.AppField name="volume">
  {field => (
    <field.Layout.Stack label="Volume">
      <field.Range
        value={field.state.value}
        onChange={field.handleChange}
        min={0}
        max={100}
        step={10}
      />
    </field.Layout.Stack>
  )}
</form.AppField>

---

Layouts

Two layout options are available for positioning labels and fields.

Stack Layout (Vertical)

Label above, field below. Best for forms with longer labels or mobile layouts.

<field.Layout.Stack
  label="Email Address"
  hintText="We'll never share your email"
  required
>
  <field.Input value={field.state.value} onChange={field.handleChange} />
</field.Layout.Stack>

Row Layout (Horizontal)

Label on left (~50%), field on right. Compact layout for settings pages.

<field.Layout.Row label="Email Address" hintText="We'll never share your email" required>
  <field.Input value={field.state.value} onChange={field.handleChange} />
</field.Layout.Row>

Compact Variant

Both Stack and Row layouts support a variant="compact" prop. In compact mode, the hint text appears as a tooltip on the label instead of being displayed below. This saves vertical space while still providing the hint information.

// Default: hint text appears below the label
<field.Layout.Row label="Email" hintText="We'll never share your email">
  <field.Input ... />
</field.Layout.Row>

// Compact: hint text appears in tooltip when hovering the label
<field.Layout.Row label="Email" hintText="We'll never share your email" variant="compact">
  <field.Input ... />
</field.Layout.Row>

// Also works with Stack layout
<field.Layout.Stack label="Email" hintText="We'll never share your email" variant="compact">
  <field.Input ... />
</field.Layout.Stack>

When to Use Compact:

• Settings pages with many fields where vertical space is limited
• Forms where hint text is supplementary, not essential
• Dashboards or panels with constrained height

Custom Layouts

You are allowed to create new layouts if necessary, or not use any layouts at all. Without a layout, you should render field.meta.Label and optionally field.meta.HintText for a11y.

<form.AppField name="firstName">
  {field => (
    <Flex gap="md">
      <field.Meta.Label required>First Name:</field.Meta.Label>
      <field.Input value={field.state.value ?? ''} onChange={field.handleChange} />
    </Flex>
  )}
</form.AppField>

Layout Props

Prop	Type	Description
label	string	Field label text
hintText	string	Helper text (below label by default, tooltip in compact mode)
required	boolean	Shows required indicator
variant	"compact"	Shows hint text in tooltip instead of below label

---

Field Groups

Group related fields into sections with a title.

<form.FieldGroup title="Personal Information">
  <form.AppField name="firstName">{/* ... */}</form.AppField>
  <form.AppField name="lastName">{/* ... */}</form.AppField>
</form.FieldGroup>

<form.FieldGroup title="Contact Information">
  <form.AppField name="email">{/* ... */}</form.AppField>
  <form.AppField name="phone">{/* ... */}</form.AppField>
</form.FieldGroup>

---

Disabled State

Fields accept disabled as a boolean or string. When a string is provided, it displays as a tooltip explaining why the field is disabled.

// ❌ Don't disable without explanation
<field.Input disabled value={field.state.value} onChange={field.handleChange} />

// ✅ Provide a reason when disabling
<field.Input
  disabled="This feature requires a Business plan"
  value={field.state.value}
  onChange={field.handleChange}
/>

---

Validation with Zod

Schema Definition

import {z} from 'zod';

const userSchema = z.object({
  email: z.string().email('Please enter a valid email'),
  password: z.string().min(8, 'Password must be at least 8 characters'),
  age: z.number().gte(13, 'You must be at least 13 years old'),
  bio: z.string().optional(),
  tags: z.array(z.string()).optional(),
  address: z.object({
    street: z.string().min(1, 'Street is required'),
    city: z.string().min(1, 'City is required'),
  }),
});

Conditional Validation

Use .refine() for cross-field validation:

const schema = z
  .object({
    password: z.string(),
    confirmPassword: z.string(),
  })
  .refine(data => data.password === data.confirmPassword, {
    message: 'Passwords do not match',
    path: ['confirmPassword'],
  });

Conditional Fields

Use form.Subscribe to show/hide fields based on other field values:

<form.Subscribe selector={state => state.values.plan === 'enterprise'}>
  {showBilling =>
    showBilling ? (
      <form.AppField name="billingEmail">
        {field => (
          <field.Layout.Stack label="Billing Email" required>
            <field.Input value={field.state.value} onChange={field.handleChange} />
          </field.Layout.Stack>
        )}
      </form.AppField>
    ) : null
  }
</form.Subscribe>

---

Error Handling

Server-Side Errors

Use setFieldErrors to display backend validation errors:

import {useMutation} from '@tanstack/react-query';

import {setFieldErrors} from '@sentry/scraps/form';

import {fetchMutation} from 'sentry/utils/queryClient';

function MyForm() {
  const mutation = useMutation({
    mutationFn: (data: {email: string; username: string}) => {
      return fetchMutation({
        url: '/users/',
        method: 'POST',
        data,
      });
    },
  });

  const form = useScrapsForm({
    ...defaultFormOptions,
    defaultValues: {email: '', username: ''},
    validators: {onDynamic: schema},
    onSubmit: async ({value, formApi}) => {
      try {
        await mutation.mutateAsync(value);
      } catch (error) {
        // Set field-specific errors from backend
        setFieldErrors(formApi, {
          email: {message: 'This email is already registered'},
          username: {message: 'Username is taken'},
        });
      }
    },
  });

  // ...
}

Important: setFieldErrors supports nested paths with dot notation: 'address.city': {message: 'City not found'}

Error Display

Validation errors automatically show as a warning icon with tooltip in the field's trailing area. No additional code needed.

---

Auto-Save Pattern

For settings pages where each field saves independently, use AutoSaveField.

Basic Auto-Save Field

import {z} from 'zod';

import {AutoSaveField} from '@sentry/scraps/form';

import {fetchMutation} from 'sentry/utils/queryClient';

const schema = z.object({
  displayName: z.string().min(1, 'Display name is required'),
});

function SettingsForm() {
  return (
    <AutoSaveField
      name="displayName"
      schema={schema}
      initialValue={user.displayName}
      mutationOptions={{
        mutationFn: data => {
          return fetchMutation({
            url: '/user/',
            method: 'PUT',
            data,
          });
        },
        onSuccess: data => {
          // Update React Query cache
          queryClient.setQueryData(['user'], old => ({...old, ...data}));
        },
      }}
    >
      {field => (
        <field.Layout.Row label="Display Name">
          <field.Input value={field.state.value} onChange={field.handleChange} />
        </field.Layout.Row>
      )}
    </AutoSaveField>
  );
}

Auto-Save Behavior by Field Type

Field Type	When it saves
Input, TextArea	On blur (when user leaves field)
Select (single)	Immediately when selection changes
Select (multiple)	When menu closes, or when X/clear clicked while menu closed
Switch	Immediately when toggled
Range	When user releases the slider, or immediately with keyboard

Auto-Save Status Indicators

The form system automatically shows:

• Spinner while saving (pending)
• Checkmark on success (fades after 2s)
• Warning icon on validation error (with tooltip)

Confirmation Dialogs

For dangerous operations (security settings, permissions), use the confirm prop to show a confirmation modal before saving. The confirm prop accepts either a string or a function.

<AutoSaveField
  name="require2FA"
  schema={schema}
  initialValue={false}
  confirm={value =>
    value
      ? 'This will remove all members without 2FA. Continue?'
      : 'Are you sure you want to allow members without 2FA?'
  }
  mutationOptions={{...}}
>
  {field => (
    <field.Layout.Row label="Require Two-Factor Auth">
      <field.Switch checked={field.state.value} onChange={field.handleChange} />
    </field.Layout.Row>
  )}
</AutoSaveField>

Confirm Config Options:

Type	Description
string	Always show this message before saving
(value) => string | undefined	Function that returns a message based on the new value, or undefined to skip confirmation

Note: Confirmation dialogs always focus the Cancel button for safety, preventing accidental confirmation of dangerous operations.

Examples:

// ✅ Simple string - always confirm
confirm="Are you sure you want to change this setting?"

// ✅ Only confirm when ENABLING (return undefined to skip)
confirm={value => value ? 'Are you sure you want to enable this?' : undefined}

// ✅ Only confirm when DISABLING
confirm={value => !value ? 'Disabling this removes security protection.' : undefined}

// ✅ Different messages for each direction
confirm={value =>
  value
    ? 'Enable 2FA requirement for all members?'
    : 'Allow members without 2FA?'
}

// ✅ For select fields - confirm specific values
confirm={value => value === 'delete' ? 'This will permanently delete all data!' : undefined}

---

Form Submission

Important: Always use TanStack Query mutations (useMutation) for form submissions. This ensures proper loading states, error handling, and cache management.

Using Mutations

import {useMutation} from '@tanstack/react-query';

import {fetchMutation} from 'sentry/utils/queryClient';

function MyForm() {
  const mutation = useMutation({
    mutationFn: (data: FormData) => {
      return fetchMutation({
        url: '/endpoint/',
        method: 'POST',
        data,
      });
    },
    onSuccess: () => {
      // Handle success (e.g., show toast, redirect)
    },
  });

  const form = useScrapsForm({
    ...defaultFormOptions,
    defaultValues: {...},
    validators: {onDynamic: schema},
    onSubmit: ({value}) => {
      return mutation.mutateAsync(value).catch(() => {});
    },
  });

  // ...
}

Submit Button

<Flex gap="md" justify="end">
  <Button onClick={() => form.reset()}>Reset</Button>
  <form.SubmitButton>Save Changes</form.SubmitButton>
</Flex>

The SubmitButton automatically:

• Disables while submission is pending
• Triggers form validation before submit

---

Do's and Don'ts

Form System Choice

// ❌ Don't use legacy JsonForm for new forms
<JsonForm fields={[{name: 'email', type: 'text'}]} />;

// ✅ Use useScrapsForm with Zod validation
const form = useScrapsForm({
  ...defaultFormOptions,
  defaultValues: {email: ''},
  validators: {onDynamic: schema},
});

Default Options

// ❌ Don't forget defaultFormOptions
const form = useScrapsForm({
  defaultValues: {name: ''},
});

// ✅ Always spread defaultFormOptions first
const form = useScrapsForm({
  ...defaultFormOptions,
  defaultValues: {name: ''},
});

Form Submissions

// ❌ Don't call API directly in onSubmit
onSubmit: async ({value}) => {
  await api.post('/users', value);
};

// ❌ Don't use mutateAsync without .catch() - causes unhandled rejection
onSubmit: ({value}) => {
  return mutation.mutateAsync(value);
};

// ✅ Use mutations with fetchMutation and .catch(() => {})
const mutation = useMutation({
  mutationFn: data => fetchMutation({url: '/users/', method: 'POST', data}),
});

onSubmit: ({value}) => {
  // Return the promise to keep form.isSubmitting working
  // Add .catch(() => {}) to avoid unhandled rejection - error handling
  // is done by TanStack Query (onError callback, mutation.isError state)
  return mutation.mutateAsync(value).catch(() => {});
};

Field Value Handling

// ❌ Don't use field.state.value directly when it might be undefined
<field.Input value={field.state.value} />

// ✅ Provide fallback for optional fields
<field.Input value={field.state.value ?? ''} />

Validation Messages

// ❌ Don't use generic error messages
z.string().min(1);

// ✅ Provide helpful, specific error messages
z.string().min(1, 'Email address is required');

Auto-Save Cache Updates

// ❌ Don't forget to update the cache after auto-save
mutationOptions={{
  mutationFn: (data) => fetchMutation({url: '/user/', method: 'PUT', data}),
}}

// ✅ Update React Query cache on success
mutationOptions={{
  mutationFn: (data) => fetchMutation({url: '/user/', method: 'PUT', data}),
  onSuccess: (data) => {
    queryClient.setQueryData(['user'], old => ({...old, ...data}));
  },
}}

Auto-Save Mutation Typing with Mixed-Type Schemas

When using AutoSaveField with schemas that have mixed types (e.g., strings and booleans), the mutation options must be typed using the schema-inferred type. Using generic types like Record<string, unknown> breaks TanStack Form's ability to narrow field types.

const preferencesSchema = z.object({
  theme: z.string(),
  language: z.string(),
  notifications: z.boolean(),
});

type Preferences = z.infer<typeof preferencesSchema>;

// ❌ Don't use generic types - breaks field type narrowing
const mutationOptions = mutationOptions({
  mutationFn: (data: Record<string, unknown>) => fetchMutation({...}),
});

// ✅ Use schema-inferred type for proper type narrowing
const mutationOptions = mutationOptions({
  mutationFn: (data: Partial<Preferences>) => fetchMutation({...}),
});

This ensures that when you use name="theme", the field correctly infers string type, and name="notifications" infers boolean type.

Layout Choice

// ❌ Don't use Row layout when labels are very long
<field.Layout.Row label="Please enter the primary email address for your account">

// ✅ Use Stack layout for long labels
<field.Layout.Stack label="Please enter the primary email address for your account">

---

Quick Reference Checklist

When creating a new form:

• Import from @sentry/scraps/form and zod
• Define Zod schema with helpful error messages
• Use useScrapsForm with ...defaultFormOptions
• Set defaultValues matching schema shape
• Set validators: {onDynamic: schema}
• Wrap with <form.AppForm> and <form.FormWrapper>
• Use <form.AppField> for each field
• Choose appropriate layout (Stack or Row)
• Handle server errors with setFieldErrors
• Add <form.SubmitButton> for submission

When creating auto-save fields:

• Use <AutoSaveField> component
• Pass schema for validation
• Pass initialValue from current data
• Configure mutationOptions with mutationFn
• Update cache in onSuccess callback

---

File References

File	Purpose
static/app/components/core/form/scrapsForm.tsx	Main form hook
static/app/components/core/form/field/autoSaveField.tsx	Auto-save wrapper
static/app/components/core/form/field/*.tsx	Individual field components
static/app/components/core/form/layout/index.tsx	Layout components
static/app/components/core/form/form.stories.tsx	Usage examples