API · Manage · Mail
Acknowledge mail.
Confirm a piece of physical mail has been read and triaged — the equivalent of clicking through a notification in a digital inbox. Acknowledgement clears the item from the entity's compliance queue and stops follow-up reminders, but does not file a response or forward the scan.
Most callers wire this into an automation: an agent classifies inbound mail (x-matter-mail-classifier does the OCR and category assignment on receipt), and acknowledges anything routine — junk filings, duplicate notices, address-update confirmations — leaving only the items that need human attention in received state.
Tier guard - Tier-4 agents (autonomous) cannot acknowledge items of category=service_of_process — lawsuits, summons, subpoenas, and tax-court notices always route through a human Authorization regardless of agent tier. The endpoint returns 403 service_of_process_requires_human if a tier-4 token attempts it.
Returns 200 OK with the updated mail item. Idempotent via Idempotency-Key. See idempotency.
See also: Mail API overview.
Last updated
Response Body
application/json
application/problem+json
application/problem+json
application/problem+json
application/problem+json
Request
curl -X POST "https://api.mattermode.com/v1/mail/{id}/acknowledge"fetch("https://api.mattermode.com/v1/mail/{id}/acknowledge", { method: "POST"})package mainimport ( "fmt" "net/http" "io/ioutil")func main() { url := "https://api.mattermode.com/v1/mail/{id}/acknowledge" req, _ := http.NewRequest("POST", url, nil) res, _ := http.DefaultClient.Do(req) defer res.Body.Close() body, _ := ioutil.ReadAll(res.Body) fmt.Println(res) fmt.Println(string(body))}import requestsheaders = { "Authorization": "Bearer sk_test_4eC39HqLyjWDarjtT1zdp7dc", "Matter-Version": "2026-06-10", "Idempotency-Key": "ee7c3a9b-3f1a-4d8e-9b2a-7c5e1f0a2d4b",}resp = requests.post( "https://api.mattermode.com/v1/mail/mail_F2sQwLtR/acknowledge", headers=headers,)resp.raise_for_status()print(resp.json())import java.net.URI;import java.net.http.HttpClient;import java.net.http.HttpRequest;import java.net.http.HttpResponse;import java.net.http.HttpResponse.BodyHandlers;import java.time.Duration;HttpClient client = HttpClient.newBuilder() .connectTimeout(Duration.ofSeconds(10)) .build();HttpRequest.Builder requestBuilder = HttpRequest.newBuilder() .uri(URI.create("https://api.mattermode.com/v1/mail/{id}/acknowledge")) .POST() .build();try { HttpResponse<String> response = client.send(requestBuilder.build(), BodyHandlers.ofString()); System.out.println("Status code: " + response.statusCode()); System.out.println("Response body: " + response.body());} catch (Exception e) { e.printStackTrace();}using System;using System.Net.Http;using System.Text;var client = new HttpClient();var response = await client.PostAsync("https://api.mattermode.com/v1/mail/{id}/acknowledge");var responseBody = await response.Content.ReadAsStringAsync();curl --request POST 'https://api.mattermode.com/v1/mail/mail_F2sQwLtR/acknowledge' \ --header 'Authorization: Bearer sk_test_4eC39HqLyjWDarjtT1zdp7dc' \ --header 'Matter-Version: 2026-06-10' \ --header 'Idempotency-Key: ee7c3a9b-3f1a-4d8e-9b2a-7c5e1f0a2d4b'const response = await fetch("https://api.mattermode.com/v1/mail/mail_F2sQwLtR/acknowledge", { method: "POST", headers: { "Authorization": "Bearer sk_test_4eC39HqLyjWDarjtT1zdp7dc", "Matter-Version": "2026-06-10", "Idempotency-Key": "ee7c3a9b-3f1a-4d8e-9b2a-7c5e1f0a2d4b", },});if (!response.ok) { throw new Error(`Matter API ${response.status}: ${await response.text()}`);}const data = await response.json();console.log(data);Response
application/json{
"id": "mail_Nq3KcAbc",
"object": "mail_item",
"entity_id": "ent_Nq3KcAbc",
"source": "registered_agent_scan",
"category": "service_of_process",
"status": "received",
"sender": {},
"return_address": {
"line1": "548 Market St",
"city": "San Francisco",
"region": "CA",
"postal_code": "94104",
"country": "US"
},
"subject": "string",
"ocr_text": "string",
"extracted": {},
"response_deadline": 0,
"received_at": 0,
"scanned_at": 0,
"scan_document_id": "string",
"response_document_id": "string",
"related_filing_id": "string",
"escalation_authorization_id": "string",
"forwarding": {},
"metadata": {},
"created": 1745539200,
"updated": 1745539200,
"livemode": false
}{
"type": "https://mattermode.com/docs/errors/authentication_required",
"title": "Authentication required",
"status": 401,
"code": "authentication_required",
"detail": "No bearer token was supplied. Pass `Authorization: Bearer sk_live_...` on every request.",
"doc_url": "https://mattermode.com/docs/guides/errors#authentication_required",
"request_id": "req_Qw9xYz8A"
}{
"type": "https://mattermode.com/docs/errors/not_found",
"title": "Not found",
"status": 404,
"code": "not_found",
"detail": "No entity with id `ent_Nq3KcAbc` is visible to this token.",
"doc_url": "https://mattermode.com/docs/guides/errors#not_found",
"request_id": "req_Qw9xYz8A"
}{
"type": "https://mattermode.com/docs/errors/invalid_state_transition",
"title": "Invalid state transition",
"status": 409,
"code": "invalid_state_transition",
"detail": "Entity ent_Nq3KcAbc is in state `dissolved`; `dissolve` is not a valid transition.",
"doc_url": "https://mattermode.com/docs/guides/errors#invalid_state_transition",
"request_id": "req_Qw9xYz8A",
"current_state": "dissolved",
"attempted_transition": "dissolve",
"allowed_transitions": []
}{
"type": "https://mattermode.com/docs/errors/dissolution_prerequisites_missing",
"title": "Dissolution prerequisites missing",
"status": 409,
"code": "dissolution_prerequisites_missing",
"detail": "Voluntary dissolution requires `board_resolution_id` and `stockholder_consent_id`, or `auto_generate_resolutions: true`.",
"doc_url": "https://mattermode.com/docs/guides/errors#dissolution_prerequisites_missing",
"request_id": "req_Qw9xYz8A"
}{
"type": "https://mattermode.com/docs/errors/valuation_stale",
"title": "409A valuation stale",
"status": 409,
"code": "valuation_stale",
"detail": "Active 409A val_AbCd1234 is older than 12 months or superseded by a material event. Issuing ISOs at the prior strike risks IRC §409A violation. Refresh via POST /entities/{id}/valuations/{id}/refresh_request.",
"doc_url": "https://mattermode.com/docs/guides/errors#valuation_stale",
"request_id": "req_Qw9xYz8A"
}{
"type": "https://mattermode.com/docs/errors/rate_limit_exceeded",
"title": "Rate limit exceeded",
"status": 429,
"code": "rate_limit_exceeded",
"detail": "Request rate exceeded for this key. Retry after `retry_after` seconds or honor the `Retry-After` header.",
"doc_url": "https://mattermode.com/docs/guides/errors#rate_limit_exceeded",
"request_id": "req_Qw9xYz8A",
"retry_after": 30
}