Get metrics
POST
/api/v3/metrics
const url = 'https://api.tryletterhead.com/api/v3/metrics';const form = new FormData();form.append('api', 'true');form.append('from', '2026-02-26');form.append('to', '2026-03-26');form.append('channels[]', 'an-example-channel');form.append('direction', 'desc');form.append('groupBy', 'channel');form.append('limit', '5');form.append('page', '1');form.append('sortBy', 'opens');
const options = {method: 'POST', headers: {Authorization: 'Bearer <token>'}};
options.body = form;
try { const response = await fetch(url, options); const data = await response.json(); console.log(data);} catch (error) { console.error(error);}curl --request POST \ --url https://api.tryletterhead.com/api/v3/metrics \ --header 'Authorization: Bearer <token>' \ --header 'Content-Type: multipart/form-data' \ --form api=true \ --form from=2026-02-26 \ --form to=2026-03-26 \ --form 'channels[]=an-example-channel' \ --form direction=desc \ --form groupBy=channel \ --form limit=5 \ --form page=1 \ --form sortBy=opensCompany-scoped send/engagement totals for a date range — accepted, bounced, clicks,
unique opens (confirmed and unconfirmed) — plus a daily sparkline and the prior period’s
totals for comparison. Pass groupBy=channel to also get a per-channel breakdown, sorted by
sortBy.
v3 endpoints expect a company API key.
Authorizations
Section titled “Authorizations ”Request Body required
Section titled “Request Body required ” Media type multipart/form-data
object
api
required
When set to true, this endpoint will accept authorization with your API Key.
string
Example
true from
required
Period start date (inclusive).
string
Example
2026-02-26 to
required
Period end date (inclusive), must be >= from, max 90 days.
string
Example
2026-03-26 channels[]
string[] | Optionally filter your metrics with a list of channels (by their identifiers).
string
Example
an-example-channel direction
Change sort direction by optionally specifying “asc” or “desc.” Descending is default.
string
Example
desc groupBy
Pass channel to include per-channel breakdown
string
Example
channel limit
Items per page for the channel breakdown. Max of 25.
string
Example
5 page
Page number for channel breakdown, as those will be paginated.
string
Example
1 sortBy
Sort by “opens” or “channel” for a channel breakdown. Defaults to “opens.”
string
Example
opensResponses
Section titled “ Responses ”Get metrics
Media type application/json
object
items
object
currentPeriod
object
totals
object
accepted
integer
bounced
integer
clicks
integer
clicksUnique
integer
opensUnique
integer
opensUniqueConfirmed
integer
unsubscribes
integer
daily
Array<object>
object
date
string
accepted
integer
bounced
integer
clicks
integer
clicksUnique
integer
opensUnique
integer
opensUniqueConfirmed
integer
priorPeriod
object
totals
object
accepted
integer
bounced
integer
clicks
integer
clicksUnique
integer
opensUnique
integer
opensUniqueConfirmed
integer
unsubscribes
integer
message
string
total
integer
Example
{ "items": { "currentPeriod": { "totals": { "accepted": 172, "bounced": 0, "clicks": 6, "clicksUnique": 2, "opensUnique": 139, "opensUniqueConfirmed": 139, "unsubscribes": 0 }, "daily": [ { "date": "2026-02-27", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-02-28", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-03-01", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-03-02", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-03-05", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-03-06", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-03-07", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-03-08", "accepted": 15, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 11, "opensUniqueConfirmed": 11 }, { "date": "2026-03-09", "accepted": 13, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 9, "opensUniqueConfirmed": 9 }, { "date": "2026-03-10", "accepted": 1, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 1, "opensUniqueConfirmed": 1 }, { "date": "2026-03-11", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-03-12", "accepted": 13, "bounced": 0, "clicks": 6, "clicksUnique": 2, "opensUnique": 12, "opensUniqueConfirmed": 12 }, { "date": "2026-03-13", "accepted": 13, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 12, "opensUniqueConfirmed": 12 }, { "date": "2026-03-14", "accepted": 12, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 10, "opensUniqueConfirmed": 10 }, { "date": "2026-03-15", "accepted": 14, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 11, "opensUniqueConfirmed": 11 }, { "date": "2026-03-16", "accepted": 12, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 9, "opensUniqueConfirmed": 9 }, { "date": "2026-03-17", "accepted": 5, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 4, "opensUniqueConfirmed": 4 }, { "date": "2026-03-18", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-03-19", "accepted": 12, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 11, "opensUniqueConfirmed": 11 }, { "date": "2026-03-20", "accepted": 12, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 11, "opensUniqueConfirmed": 11 }, { "date": "2026-03-21", "accepted": 12, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 10, "opensUniqueConfirmed": 10 }, { "date": "2026-03-22", "accepted": 14, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 8, "opensUniqueConfirmed": 8 }, { "date": "2026-03-23", "accepted": 12, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 9, "opensUniqueConfirmed": 9 }, { "date": "2026-03-24", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-03-25", "accepted": 0, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 0, "opensUniqueConfirmed": 0 }, { "date": "2026-03-26", "accepted": 12, "bounced": 0, "clicks": 0, "clicksUnique": 0, "opensUnique": 11, "opensUniqueConfirmed": 11 } ] }, "priorPeriod": { "totals": { "accepted": 160, "bounced": 1, "clicks": 0, "clicksUnique": 0, "opensUnique": 119, "opensUniqueConfirmed": 117, "unsubscribes": 0 } } }, "message": "Do something kind today", "total": 1}400 Validation Error — from/to missing or malformed.
Media type application/json
object
data
Array<string>
items
Array<object>
object
message
string
total
integer
Example
{ "data": [ "The from field is required." ], "items": [], "message": "Looks like the input data doesn't meet our requirements.", "total": 0}422 Unprocessable Entity — from is after to, or the from/to range exceeds 90 days.
Media type application/json
object
data
Array<string>
items
Array<object>
object
message
string
total
integer
Example
{ "data": [ "Date range must not exceed 90 days." ], "items": [], "message": "Looks like the input data doesn't meet our requirements.", "total": 0}Still can’t find what you need? Contact support.