How to schedule Tumblr posts in its own format

Tumblr has its own queue and a way to set a publish time, so scheduling on Tumblr is possible without any tool. A scheduler is for keeping a blog in step with the other networks: one post, written once, goes to Tumblr in its own post format at the time you chose, hashtags on the last line become tags, and the notes come back to one inbox. This page explains how that works through Tumblr's API, which limits matter, and why a post can be late without being lost.

What a Tumblr post holds

Tumblr posts in its own Neue Post Format (NPF), a list of blocks, and a scheduler builds those blocks from the post.

Media goes first and the words sit under it, which is how a Tumblr photo post reads. Hashtags inside the text stay text, because Tumblr does not link them there. Tumblr has no character limit worth naming; Preflight holds a post to 250,000 characters only as a sanity ceiling.

Preflight's clock, not Tumblr's queue

The API can queue a post with a publish time, and Tumblr's queue has its own rules: a blog can hold 1,000 queued posts and the queue publishes at most 50 a day at its fastest setting. Preflight does not use the queue. It holds the post and publishes it at the chosen minute, so the post counts toward the daily total when it goes out. For most blogs that makes no difference.

The limits that matter

• 250 published posts a day. Tumblr's documentation allows 250 new published posts per user per day, reblogs included, resetting on Tumblr's own clock. A schedule of a few posts a day is far from it; a burst of imports is not. Queued posts do not count toward the 250.
• Posts, pictures and videos have daily allowances. When a blog reaches one, Tumblr answers with a 403 error that a tool must treat as waiting. Preflight tries again about every six hours, up to eight times. If the blog is still processing an earlier video, it tries again after ten minutes. The post's row says which, so a post that is late is never a post that is lost.
• The app has a call budget. The API allows 1,000 calls an hour and 5,000 a day per app key, shared by every user of the app. Background work such as reading notes stops at 600 an hour and 3,500 a day so publishing keeps the rest, and a 429 answer is honoured by waiting.

Which blog gets the post

The connected blog is the primary blog on the Tumblr account. Posting to a secondary blog is not offered, because Tumblr rotates the refresh token every time it is used and several connections sharing one grant would invalidate each other. To post to another blog, connect a Tumblr login whose primary blog it is. Connecting asks for three scopes, basic, write and offline access, and the last is what gives a refresh token so the connection does not expire between posts. If the token is revoked, the channel shows as needing reconnection and reconnecting fixes it.

What a tool cannot do on Tumblr

• Edit a published post from Preflight. Tumblr's API has a route for it, but Preflight does not call it; change the post on Tumblr or delete and post again.
• Answer replies, asks, reblog or read the dashboard. Preflight reads the replies under a post and shows them in the inbox. It does not answer them.
• Report views. Notes arrive as totals and a list. The figures are likes, reblogs and replies and nothing more.

Scheduling it in Preflight

Connect your Tumblr account, tick Tumblr with the other networks, write the post once and set a time. The composer checks the pictures (JPEG, PNG or GIF, 20 MB each, more than 30 warned about as dropped), the single video of at most 500 MB and ten minutes, and refuses an empty post. The checks run the same from the app, the API and the MCP server. Tumblr is on every plan, the free one included (see pricing); the integration page with all the scopes and policies is Tumblr scheduler, and the limits of every network are on the limits table.