---
title: "Update up to 1,000 contacts that already exist."
method: POST
path: "/contacts/batch"
tags: ["contacts"]
---

# Update up to 1,000 contacts that already exist.

`POST /contacts/batch`

## Request

- Base URL: `https://api.agentisend.com`
- URL: `https://api.agentisend.com/contacts/batch`
- Auth: HTTP bearer

A new address is rejected.

## Headers

- `Idempotency-Key` string
- `Resend-Idempotency-Key` string

## Request body

- PostContactsBatchBody
  - `contacts` object[], required: Contacts to update. At most 1,000. A new address is rejected.
    - `email` string, required: The contact address. A new address is rejected; an existing one is updated.
    - `first_name` string, nullable: Given name. Null clears it.
    - `last_name` string, nullable: Family name. Null clears it.
    - `unsubscribed` boolean: true stops marketing mail to this address.
    - `status` 'active' | 'unsubscribed': active, or unsubscribed to stop marketing mail.
    - `properties` object: Named values stored on the contact. A new name is created.

## Response `200`

Success

- PostContactsBatchReply
  - `data` object[], required
    - `index` integer, required
    - `status` 'created' | 'updated' | 'rejected', required
    - `id` string, uuid
    - `email` string
    - `error` object
      - `code` string, required
      - `message` string, required
      - `fix` string, required
      - `docs_url` string, required

## Other responses

- `400`: The request is malformed or a field failed validation. Codes: validation_error, invalid_idempotency_key, invalid_cursor, plan_not_purchasable, stripe_signature_invalid, support_upload_rejected, sign_in_check_required.
- `409`: The request conflicts with the current state. Codes: domain_already_exists, template_name_taken, template_alias_taken, template_in_use, segment_in_use, contact_resubscribe_required, email_still_scheduled, domain_verified_elsewhere, domain_not_claimable, return_path_subdomain_in_use, overage_not_on_plan, term_not_on_sale, subscription_active, portal_change_unavailable, already_in_account, idempotency_in_flight, idempotency_payload_mismatch, approval_expired, support_closed, support_reopen_expired, support_merge_conflict, support_reply_too_soon.
- `413`: The request body is larger than this operation accepts. Codes: payload_too_large, support_upload_too_large.
- `415`: The request body is not JSON. Codes: unsupported_media_type.
- `429`: A rate, quota or ramp ceiling was reached. Codes: onboarding_daily_cap_reached, trust_throttled, invite_limit_reached, rate_ceiling_exceeded, daily_quota_exceeded, monthly_quota_exceeded, rate_limit_exceeded, support_rate_limited.
- `500`: Something failed on our side. Codes: internal_server_error.

---

[API](https://skmtc.dev/agentisend/apis/agentisend-api.md) · [All operations](https://skmtc.dev/agentisend/apis/agentisend-api/llms.txt) · [OpenAPI document](https://skmtc.dev/agentisend/apis/agentisend-api/revisions/3066dda62a56?raw)