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Custom metadata lets you attach information to each interview by adding parameters to your study link. Use it to identify users, track campaign sources, and segment your results. Append query parameters with the meta_ prefix to your study URL. The prefix is stripped automatically, so meta_source becomes source in your dashboard.
Study link with metadata
You can add as many parameters as you need:
Multiple parameters

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Example use cases

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Track where interviews come from

Source tracking

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Segment by user attributes

Plan and role
User and org IDs

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What Pillow captures automatically

Every interview automatically records system metadata, no URL parameters needed: This appears alongside your custom metadata in the interview view.

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Viewing metadata

Open an interview and click the Metadata button in the footer bar. The panel shows:
  • Metadata: Your custom meta_ parameters
  • System: Locale, location, device, and user-agent

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Filtering interviews by metadata

Click the filter icon in the interview list, then scroll to the Metadata section. Click Add to pick a metadata key, then select specific values to filter by. This is where consistent naming pays off: if all your email campaigns use meta_source=email, you can filter to just those interviews in one click.

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Limits

Keys can contain letters, numbers, underscores, dots, and dashes. Pillow truncates values that exceed the limit.

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Best practices

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Keep keys short and consistent

Use short, descriptive keys after the prefix:
  • ✅ meta_plan, meta_source, meta_user_id
  • ❌ meta_user_subscription_plan_type, meta_marketing_campaign_source

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Standardize values

Pick a casing convention and stick to it:
  • ✅ meta_plan=pro, meta_plan=free, meta_plan=enterprise
  • ❌ meta_plan=Pro, meta_plan=FREE, meta_plan=Enterprise Plan

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Avoid sensitive data

Never pass sensitive information in URLs. URL parameters are visible in browser history, server logs, and analytics tools.Avoid: passwords, API keys, personal health information, financial data.

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FAQ

No. Metadata is captured when the user first opens the link. You can’t add or modify metadata for existing interviews.
You can add up to 50 parameters per prefix. The total URL should stay under roughly 2,000 characters to avoid issues with email clients and messaging platforms.

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What’s next

Broadcast your study

Put your metadata-tagged links to work.

Review interviews

See metadata in the interview view.