Resends and subject tests

Both work on newsletter posts (/newsletters/posts). Product guide: Resends and subject tests.

Growth plan and above. Scheduling a resend and starting a subject test answer 403 with code: FEATURE_LOCKED below it. Reading and cancelling stay open. Every email counts toward your monthly sends and goes through the same checks as POST /newsletters/posts/{id}/send (402 SEND_ALLOWANCE_EXCEEDED, 429 DAILY_SEND_LIMIT, …).

Endpoints

Method	Endpoint	Operation ID	MCP tool
`GET`	`/newsletters/posts/{id}/resend`	`getPostResend`	`get_post_resend`
`POST`	`/newsletters/posts/{id}/resend`	`scheduleResendToNonOpeners`	`resend_to_non_openers`
`DELETE`	`/newsletters/posts/{id}/resend`	`cancelResendToNonOpeners`	`cancel_resend`
`GET`	`/newsletters/posts/{id}/subject-test`	`getSubjectTest`	`get_subject_test`
`POST`	`/newsletters/posts/{id}/subject-test`	`startSubjectTest`	`start_subject_test`

Resend to non-openers

curl -X POST https://api.pocketsflow.com/newsletters/posts/POST_ID/resend \
  -H "Authorization: Bearer pk_live_..." \
  -H "Content-Type: application/json" \
  -d '{ "subject": "In case you missed it: the spring drop", "delayHours": 48 }'

The resend is scheduled delayHours (1–168, default 48) after the original send, and never sooner than 10 minutes from now. When it runs it goes to everyone who received the post (or one of its subject-test arms), has not opened it and is still subscribed. It is its own post (resend.postId). GET answers recipients, opened, openRate, nonOpeners (who it would go to right now), eligible with a reason when not (NOT_SENT, ALREADY_SCHEDULED, ALREADY_RESENT, NO_NON_OPENERS, …) and resend with its status and its own sent / opened / openRate.

Subject tests

curl -X POST https://api.pocketsflow.com/newsletters/posts/POST_ID/subject-test \
  -H "Authorization: Bearer pk_live_..." \
  -H "Content-Type: application/json" \
  -d '{ "subjectB": "20% off the spring drop", "testPercent": 20, "waitHours": 4 }'

Call it on a draft instead of /send. Subject A (the post’s subject) and B go to two random halves of a testPercent slice (10–50, default 20) right away; after waitHours (1–72, default 4) the subject with the higher unique open rate wins (a tie keeps A), and the post is sent with it to everyone else. The post stays scheduled until then. The audience needs at least 50 subscribers (400 AUDIENCE_TOO_SMALL). GET answers subjectTest (settings, status: testing | decided, winner, results), arms.A / arms.B with live unique opens, and rest, the winner’s send.

Opens

Opens are unique per person: every campaign email carries a signed 1×1 tracking image and the first load counts. Image blocking and privacy proxies make any open count approximate.

SDK

await pocketsflow.posts.resendToNonOpeners(postId, { subject: "Did you see this?" });
await pocketsflow.posts.startSubjectTest(postId, { subjectB: "Another subject" });
const test = await pocketsflow.posts.getSubjectTest(postId);

Overview

API reference

Node.js SDK

Webhooks

Endpoints

Resend to non-openers

Subject tests

Opens

SDK

​Endpoints

​Resend to non-openers

​Subject tests

​Opens

​SDK

Endpoints

Resend to non-openers

Subject tests

Opens

SDK