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What you’ll learn: what a computed field is, how one computed field can feed another, and how the four-level chain that turns user input into a QR code is wired.What you’ll build: UTM Campaign (Concatenation), Tagged URL (Tagged URL), Short URL (Short URL), and QR Code (QR Code), in that dependency order.Prerequisites: Part 6: The UTM cascade.

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Why this matters

Every part up to here has been about what a user types. This part is the payoff: no user input, four new fields, and the shape of the final record. A campaign creator fills in a name, a goal, a country, a date, and a URL, and the system produces a canonical UTM campaign string, a fully tagged URL, a branded short URL, and a QR code, every time, without touching any of those values. When the marketing team says “our UTM format changed,” you edit the UTM Campaign setup once on the governance model, publish, and every record created after that follows. That is the leverage computed fields buy you.

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Concepts first

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Computed fields

A computed field has no input cell on the submission form. Its value is derived from other fields on the same row, recomputed as the user types (a live preview) and again authoritatively when the submission is saved. Computed fields are always required and cannot be edited by submitters. The Short URL field in this part is a partial exception: its slug is generated, but with Auto-generated, editable someone can override it before approval. The value is stored on the record once the submission is approved, so downstream systems read a computed field the same way they read any other.

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Dependency chains

A computed field’s inputs can themselves be computed fields. When the row is saved, Terminus fills in each computed field as soon as its inputs are ready, repeating until every value settles. That is how QR Code can depend on Short URL, which depends on Tagged URL, which depends on UTM Campaign: four levels deep, resolved in one pass. You never maintain an order; Terminus works it out from how the fields reference each other (and rejects a setup that would depend on itself).

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The four types used here

Terminus ships more computed field types than this tutorial covers. The four used in the Campaign URL Builder are:
  • Concatenation: joins other fields’ values with a separator.
  • Tagged URL: takes a base URL and appends query parameters sourced from other fields.
  • Short URL: creates a shortened link that redirects to a destination URL (here, the tagged URL).
  • QR Code: generates a QR image from another field’s value. Here the source is the Short URL.
Auto Number, Random, Constant, and Terminus ID are covered in the other computed fields recipe. Auto-fill, which derives a value from other fields with rules or an expression, has its own reference page.

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The chain we’re building

Five user-input fields feed UTM Campaign. UTM Campaign plus Destination URL feed Tagged URL. Tagged URL feeds Short URL. Short URL feeds QR Code. Build them in that order.

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Step-by-step

1

Create UTM Campaign (Concatenation)

With the Marketing governance model open, click Fields in the sidebar, then Create new, and pick Concatenation. Name: UTM Campaign. Under Field parts, add, in order: Goal, Country, Region, Launch Date, Campaign Name. Separator: -. Turn on Remove extra separators. Click Save to draft.
Why Remove extra separators: it collapses runs of empty parts into a single separator. If a user leaves Region blank, the output is awareness-us-2026_11_15-black_friday_2026 instead of awareness-us--2026_11_15-black_friday_2026: one dash between parts, never two. (Its alternative, Empty field replacement, substitutes a placeholder for each empty part instead; you can use one or the other, not both.)
2

Create Tagged URL (Tagged URL)

Click Create new and pick Tagged URL. Name: Tagged URL. Base URL field: Destination URL. Under URL parameters, click Add parameter three times and fill in each row: key utm_medium with Value field UTM Medium, key utm_source with UTM Source, and key utm_campaign with UTM Campaign. Click Save to draft. The Key is what appears in the query string; the Value field supplies the value. Values are percent-encoded by default (the Encode checkbox).
A new parameter’s Value field starts as Set per taxonomy. Pick the field on every row. A parameter left on Set per taxonomy must be given a source in each taxonomy that uses Tagged URL, and until it is, publishing fails with a message like “utm_source has no source in Email Campaigns. Bind a field or mark it not used.”
3

Create Short URL (Short URL)

Click Create new and pick Short URL. Name: Short URL. Destination URL field: Tagged URL (the computed field you just created, one step up the chain). Leave Shortener domain on the default Terminus Hub shortener domain. Slug mode: Auto-generated, editable. Slug size: 8. Click Save to draft.
Why auto-generated, editable: the system picks a random slug for every new record, but someone editing the submission can override it before approval if they want a memorable one. The slug size default is 10; the tutorial uses 8 to match the example output. The short URL slug modes recipe covers the other two modes (Auto-generated, read-only and Entered manually).
4

Create QR Code (QR Code)

Click Create new one last time and pick QR Code. Name: QR Code. Source field: Short URL. Click Save to draft. Because the source is a Short URL, the QR encodes the short link’s redirect address (with a qr marker added so scans can be told apart from clicks), not the tagged URL directly. If the short link’s destination is ever changed, every QR code already printed still works.
📸 Screenshot coming soon: part 07 computed field preview

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Check your work

  • Four new generated fields exist on the Marketing governance model: UTM Campaign, Tagged URL, Short URL, QR Code.
  • The governance model now has twelve fields total: eight user-input (from Parts 3 to 6) plus the four generated ones.
  • Reopen UTM Campaign from the field list. On a wide screen, a Preview panel beside the settings shows the field with its input fields. Enter sample values and UTM Campaign updates. The preview covers one step of the chain: when an input is itself computed (as Tagged URL is for Short URL), it shows a stand-in value instead. You see the whole chain resolve in Part 8.
  • No field is on a taxonomy yet. That is still Part 8.

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What you just built

The full computed chain. The governance model now carries every rule needed to turn a handful of campaign inputs into a fully tagged, shortened, QR-coded link. Below is the chain with a sample submission’s values flowing through it. Sample output for Campaign Name = "Black Friday 2026", Goal = awareness, Country = us, Region = california, Launch Date = 2026-11-15, Destination URL = https://shop.acme.example/deals, UTM Medium = email, UTM Source = newsletter:
(go.acme.example and the slug aB3xK9q2 are illustrative. Your account has its own shortener domain, and each record gets its own slug.)

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Gotchas

  • A computed field needs its inputs filled to produce a value. If Region is blank, UTM Campaign still computes (thanks to Remove extra separators), but if Destination URL is blank, Tagged URL has no base to attach parameters to and its preview stays empty until a URL is entered.
  • Point the QR Code at the Short URL, not the tagged URL. The Source field picker accepts most field types, including URL and Tagged URL fields. Encoding the long tagged URL would bake the full query string into the image, and the code would not follow the short link if its destination changes.
  • Short URLs are draft until the submission is approved. The slug is reserved on the row and shown in the preview, but the redirect is not live until approval promotes the row to a record. Grabbing a QR code from an unapproved submission will not resolve yet. See the submission pipeline for how a draft becomes a record, and the short URL reference for the field itself.
  • Reordering Concatenation parts is a real change, not a display tweak. If you swap Country and Region in UTM Campaign after approved records exist, those old records keep awareness-us-california-…; only new records get the new order. There is no retroactive recompute, so pick the order carefully.

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Next up

Part 8: Your first submission. Assemble three taxonomies, set their option filters for real, and run a campaign from draft through to approved records. For tagged URLs in isolation, see the tagged URL recipe.