Beyond triggering mail, LettrLabs can also work in the other direction: pulling closed deals and purchases from your CRM back into LettrLabs so you can see which mailers actually drove revenue. This is done by sending conversion events — a sale, a booked job, a closed deal — from your CRM into LettrLabs, where they're matched against your recipient lists to attribute revenue back to the mailing that (most likely) drove it.
Before you start
A LettrLabs API key (see Step 1 of the Setup Guide above if you don't already have one).
A CRM or other system connected to Zapier that can tell you when a deal closes or a purchase happens, along with the customer's name, address, and the deal/order value.
Step 1: Set up your CRM trigger in Zapier
In Zapier, choose your CRM (HubSpot, Salesforce, AccuLynx, etc.) as the trigger app, and pick the event that represents a completed sale — for example, a deal stage changing to "Closed Won," or a new paid invoice. Pick the specific stage or event where revenue is actually booked, since that's what determines attribution accuracy.
Step 2: Send the conversion to LettrLabs
For the action step, authenticate using the same LettrLabs API key from the Setup Guide, then send the conversion data to LettrLabs so it can be matched against your mailed recipients.
Unverified: whether this action is currently exposed as a dedicated, pre-built "LettrLabs" action inside Zapier's app directory (the way the Integration Order actions are), or whether it's set up as a raw authenticated API call (e.g. via Zapier's built-in "Webhooks by Zapier" action) against LettrLabs' conversions endpoint. The underlying LettrLabs API that accepts these events is confirmed in the codebase; the exact configuration screen a customer sees inside Zapier for this specific action was not confirmed.
Step 3: Map your deal data
Map as many of the following fields as your CRM has available — the more you provide, the more confidently LettrLabs can match the conversion to a specific mail recipient:
Name: first/last name, full name, or business name.
Address: a full address string, or split into address line 1/2, city, state, zip, and country. LettrLabs also accepts a secondary address if your CRM tracks one.
Email and phone: primary (and optionally secondary) email and phone number.
Revenue: the deal or order value. Currency symbols, commas, and spaces are all accepted (e.g.
$3,000.53); if left blank it defaults to 0.Event date: when the sale happened. Accepts most common date formats; if omitted, it defaults to whenever the event is processed.
Order ID / Customer ID / CRM ID / Store ID: your own internal identifiers, kept for reference and de-duplication.
Coupon code: if the sale is tied to a specific offer code from your campaign.
You need at least one identifier LettrLabs can match on — an address, email, phone number, or coupon code.
Step 4: Test and publish
Run Zapier's test with a real or sample deal. LettrLabs validates the record and, for anything sent successfully, returns confirmation you can inspect in Zapier before publishing. Records that fail validation (for example, missing every possible matching identifier) are rejected with details on what to fix. Once the test looks right, publish your Zap.
How matching works
As conversions come in, LettrLabs compares the address, email, phone, and/or coupon code against the recipients on your mail campaigns. When it finds a match, the revenue from that conversion is attributed back to the mailer that recipient received — so you can see, per campaign, how much closed revenue it's actually responsible for rather than relying on manual tracking or guesswork.
Checking on your conversions
You (or your integration) can look up previously submitted conversions and their processing status at any time, and remove one if it was sent in error — useful if a deal falls through after you've already reported it as a conversion.
Why this matters
Closed-loop attribution: connect mail sends to actual sales without manual tagging.
CRM-agnostic: works with any CRM or system Zapier can connect to.
Better data, better matches: the more fields you send with each conversion, the more reliably LettrLabs can tie it back to the right recipient and campaign.
Example: a roofing company closes a $9,800 deal in their CRM. A Zap sends the deal value and customer address to LettrLabs. LettrLabs matches the address against recipients from a mailer sent two weeks earlier, attributing the $9,800 back to that campaign.