Sync Custom Field Changes to Zapier

Custom fields hold actual values on a contact — a plan tier, a discount code, a preferred language — rather than the yes/no labels that tags give you. New or Updated Custom Field fires whenever one of those values is set or changed, which makes it the most detailed trigger the integration has.

One Zap watches one field

Unlike the other triggers, this one asks a question on the Configure tab: which field? The dropdown lists every custom field on your account, and the Zap only fires for the one you choose.

Pick the field to watch — the Zap ignores changes to every other field

So watching three fields means three Zaps. That sounds like duplication, and it’s actually the useful part: a plan_tier change and a preferred_language change should almost never do the same thing downstream, and separate Zaps let you send them separate places without a filter step.

The field has to exist before the Zap can watch it

The dropdown reads your live LinktoDM fields. If the one you want isn’t there, create it first — the Set user field action in a flow has a + Create new field button — then hit Refresh in the Zapier dropdown.

Mapping the value

On the action side it behaves like any other trigger: click a field, pick Custom Field from the LinktoDM step, and the value flows through.

The changed value mapped into the downstream action

Previous value is the interesting part

The payload carries the field’s previous value next to the new one. That’s what turns this from a sync into something you can act on, because the change is usually the story rather than the number.

• Tier upgrades. Watch plan_tier and post “Priya moved silver → gold” into your sales channel. Both halves of that sentence come from the one event, and a Zapier filter on the previous value lets you treat an upgrade differently from a downgrade.
• Codes and coupons. Watch a discount_code field, have Zapier create the matching coupon in Shopify, and write the result back to the contact.
• Routing. Watch preferred_language and assign the conversation to the right person on your team in Intercom or HubSpot.
• Quiz and survey answers. A flow that stores an answer with Set user field can hand every response straight to a sheet, so a DM quiz doubles as research you can actually read.
• An audit trail. Append every change to a log sheet — field, old value, new value, timestamp — and you can answer “when did this contact become a customer?” months later.

A no-op save still counts as a change here

Unlike the email and phone triggers, this one is about the field being set, so writing the same value again can fire it. If your flow re-saves a field on every message, put a condition in front of the Set user field action, or add a Zapier filter comparing the value to the previous one.

A flow and a Zap, together

LinktoDM flow:  User replies "GOLD" → Set user field (plan_tier = gold)
Zapier:         plan_tier changed → Slack message → row appended to sheet

The flow decides who qualifies and the Zap does the paperwork. Neither needs to know about the other, which is why you can change the flow’s wording ten times without touching the Zap.