Output Schemas

An output schema defines the exact JSON structure you want Meter to return from extractions. Instead of getting whatever field names the AI chooses, you specify the fields, types, and nesting — and Meter maps the extracted data to match.

When to use output schemas

You need consistent field names across different strategies (e.g., all product scrapers return price, not cost or product_price)
You want type coercion (prices as numbers, not strings like "$19.99")
Your downstream system expects a specific JSON shape
You’re using strategy groups and want uniform output across all members

Defining a schema

A schema is a JSON object where keys are field names and values are type strings:

{
  "title": "string",
  "price": "number",
  "in_stock": "boolean",
  "tags": "array",
  "image_url": "string"
}

Supported types

Type	Description	Coercion behavior
`string`	Text value	Converts to string, `None` if empty
`number`	Decimal number	Strips `$`, `€`, `£`, commas; parses float (e.g., `"$19.99"` → `19.99`)
`float`	Same as `number`	Alias for `number`
`integer`	Whole number	Same stripping as `number`, then rounds to int (e.g., `"225 points"` → `225`)
`int`	Same as `integer`	Alias for `integer`
`boolean`	True/false	`"true"`, `"yes"`, `"1"` → `True`; `"false"`, `"no"`, `"0"` → `False`
`array`	List of values	If string, splits on commas; if single value, wraps in list

Nested schemas

You can define nested structures:

{
  "product": {
    "name": "string",
    "pricing": {
      "amount": "number",
      "currency": "string"
    }
  },
  "seller": {
    "name": "string",
    "rating": "float"
  }
}

Meter flattens extracted data internally using underscore-separated keys (e.g., product_name, product_pricing_amount) and then re-nests it to match your schema structure.

Wrapper array pattern

For schemas with a single top-level key containing an array, Meter automatically wraps results:

{
  "listings": [
    {
      "title": "string",
      "price": "number"
    }
  ]
}

This produces output like:

{
  "listings": [
    {"title": "MacBook Pro", "price": 1999},
    {"title": "iPad Air", "price": 599}
  ]
}

Where schemas apply

Strategy generation

Pass an output_schema when generating a strategy to guide extraction and get consistent output from the start:

result = client.generate_strategy(
    url="https://shop.com/products",
    description="Extract product listings",
    name="Product Scraper",
    output_schema={
        "product_name": "string",
        "price": "number",
        "rating": "float",
        "in_stock": "boolean"
    }
)

# Preview data matches the schema structure
for item in result["preview_data"]:
    print(f"{item['product_name']}: ${item['price']}")

Strategy groups

Apply a schema to all strategies in a group at once:

client.apply_group_schema(
    group_id="group-uuid",
    output_schema={
        "title": "string",
        "price": "number",
        "url": "string"
    }
)

See Strategy Groups for details.

Bulk upload

When using Bulk Upload, you can define an output schema that applies to all generated strategies in the batch.

URL field handling

Meter automatically detects URL fields in your schema (keys containing url, link, or href) and optimizes extraction to capture the href attribute rather than link text. You don’t need to configure this — it happens automatically.

Examples

E-commerce product schema

{
  "product_name": "string",
  "price": "number",
  "original_price": "number",
  "discount_percentage": "integer",
  "rating": "float",
  "review_count": "integer",
  "in_stock": "boolean",
  "image_url": "string",
  "product_url": "string"
}

Job listing schema

{
  "title": "string",
  "company": "string",
  "location": "string",
  "salary_min": "integer",
  "salary_max": "integer",
  "job_type": "string",
  "posted_date": "string",
  "apply_url": "string",
  "tags": "array"
}

Next steps

Strategy Groups

Apply schemas to many strategies at once

Filtering

Filter extraction results post-processing

Strategies

Learn how strategies use output schemas

Bulk Upload

Create many strategies with a shared schema

Need help?

Email me at mckinnon@meter.sh

Getting Started

Core Concepts

Output Schemas

Output Schemas

When to use output schemas

Defining a schema

Supported types

Nested schemas

Wrapper array pattern

Where schemas apply

Strategy generation

Strategy groups

Bulk upload

URL field handling

Examples

E-commerce product schema

Job listing schema

Next steps

Strategy Groups

Filtering

Strategies

Bulk Upload

Need help?

​Output Schemas

​When to use output schemas

​Defining a schema

​Supported types

​Nested schemas

​Wrapper array pattern

​Where schemas apply

​Strategy generation

​Strategy groups

​Bulk upload

​URL field handling

​Examples

​E-commerce product schema

​Job listing schema

​Next steps

Strategy Groups

Filtering

Strategies

Bulk Upload

​Need help?

Output Schemas

When to use output schemas

Defining a schema

Supported types

Nested schemas

Wrapper array pattern

Where schemas apply

Strategy generation

Strategy groups

Bulk upload

URL field handling

Examples

E-commerce product schema

Job listing schema

Next steps

Need help?