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Post to Tumblr and read it back from one API.

Publish to Tumblr and run its tools from your app or your AI agent, with the same API key and MCP server.

Live Connects with OAuth Receives posts 2 tools

What you can post

Tumblr limits.

These are the limits the API enforces for Tumblr, read straight from the code. Every post is checked against them before anything is sent.

Posts to your primary blog, or to another blog you can post to with the blog option. Powered by Tumblr.
Each line of text becomes a paragraph. A post can carry up to 10 images and one video.
Text
100,000 codepoints
Images
Up to 10 per post · JPEG, PNG, WEBP, GIF · 20 MB each
Video
Up to 1 per post · MP4, MOV · 60 MB
Images and video together
Allowed
overrides.tumblr.blog
string · The blog to post to: its name (e.g. "myblog") or UUID, from the list_blogs tool. Leave it out to post to the primary blog.
overrides.tumblr.title
string · A heading shown above the post, up to 4,096 characters.
overrides.tumblr.tags
array · Tags for the post, without the #.
overrides.tumblr.link
string · An http(s) URL shown as a link preview card under the text.

Post with one request

Your first Tumblr post.

Send the text and the account ID. Add an Idempotency-Key so a retried request never posts twice. The response lists each account with its own status and, once it’s live, the post’s URL.

curl https://socialhelper.app/api/v1/posts \
  -H "Authorization: Bearer $SOCIALHELPER_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{
      "text": "We just shipped dark mode. Try it tonight 🌙",
      "accounts": [
          "ACCOUNT_ID"
      ]
  }'

Tools

Tumblr tools.

Call them with POST /api/v1/accounts/{id}/tools/{tool}, or let your agent use list_account_tools and run_account_tool over MCP. Results come back straight away.

list_blogs

read-only

List the blogs this Tumblr account can post to, with each blog's name and UUID (use either as the post's blog option), title, URL, followers and whether it is the primary blog.

post_notes

read-only

Count the notes (likes, reblogs and replies) on one post.

post_id* string
The post's ID, as returned when it was published.
blog string
The blog the post is on (name or UUID). Defaults to the primary blog.

Connect

Connect Tumblr once.

Open Accounts in the SocialHelper dashboard and choose Tumblr. You sign in on Tumblr’s own screen and approve access; SocialHelper stores the connection encrypted. You don’t need a Tumblr developer app of your own.

  1. 1

    Open Accounts

    In the dashboard, choose Tumblr.

  2. 2

    Sign in on Tumblr

    Approve access on Tumblr’s own screen.

  3. 3

    Use the account ID

    GET /api/v1/accounts lists the account with its ID, whether it can publish, and its tools.

SocialHelper calls Tumblr’s official API for you. Tumblr API reference ↗

FAQ

Tumblr questions.

How long can a Tumblr post be?

100,000, counted the way Tumblr counts it. SocialHelper checks the length before posting, and if it doesn’t fit nothing is sent.

Can I post images or video to Tumblr?

Up to 10 images per post. Up to 1 video per post.

Do I need my own Tumblr developer app?

No. You connect with a normal Tumblr sign-in through SocialHelper’s own app.

Can my AI agent use Tumblr?

Yes. Connect the SocialHelper MCP server at https://socialhelper.app/mcp and your agent can post to Tumblr and run its tools.

How much does it cost?

SocialHelper is free during early access, Tumblr included.

Ship your Tumblr integration today.

SocialHelper is invite-only during early access. Join the waitlist: the first 100 people to sign up get a Founding account with higher limits, free for 12 months.