Post Packs API

Post Packs are one-time credit bundles that extend your monthly post quota. Available to Starter plan and above.

Purchase a Pack

POST /packs/purchase

Parameter	Type	Required	Default	Description
`pack_type`	string	No	`"100"`	`"100"` ($10 for 100 posts) or `"300"` ($25 for 300 posts)

curl -X POST https://api.postlark.ai/v1/packs/purchase \
  -H "Authorization: Bearer pk_live_xxxxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{ "pack_type": "100" }'

{
  "message": "Post Pack 100 purchase initiated. Complete payment via Paddle checkout.",
  "pack_type": "100",
  "price": "$10",
  "posts": 100
}

Check Balance

GET /packs/balance

Returns the total remaining pack credits and a breakdown of each active pack.

curl https://api.postlark.ai/v1/packs/balance \
  -H "Authorization: Bearer pk_live_xxxxxxxxxxxx"

{
  "balance": 150,
  "packs": [
    {
      "balance": 50,
      "purchased_at": "2026-03-01T12:00:00Z"
    },
    {
      "balance": 100,
      "purchased_at": "2026-03-20T08:00:00Z"
    }
  ]
}

How Packs Work

Post Packs supplement your monthly subscription quota:

Monthly quota is consumed first — each billing cycle resets your plan’s included posts
Pack credits are used for overflow — when monthly quota runs out, posts are deducted from your oldest pack
Packs never expire — unused credits carry over indefinitely
FIFO order — the oldest pack is consumed first

Pack	Price	Posts	Per-post cost
Pack 100	$10	100	$0.10
Pack 300	$25	300	$0.083

Errors

Status	Cause
400	Invalid `pack_type` (must be `"100"` or `"300"`)
400	Blog not resolved
403	Free plan — upgrade required

See also: Rate Limits | Authentication | Blogs API