Connect Lemmy first
- 01
Open Accounts in 1Post and choose Connect, then Lemmy.
- 02
Enter your instance address, username and password. They are stored encrypted.
- 03
Choose the communities in the composer.
Then GET /v1/accounts returns the id of the Lemmy account to use in the request.
Send a post to Lemmy
curl https://api.get1post.com/v1/posts \
-H "Authorization: Bearer $ONEPOST_API_KEY" \
-H "Idempotency-Key: lemmy-first-post" \
-d '{"accounts":["ACCOUNT_ID"],"text":"Weekly thread: what are you building?","schedule_at":"2026-11-02T15:00:00Z"}'The reply is 202 with the post (status scheduled) and one destination for Lemmy, which moves from queued to published or failed.
What you can send to Lemmy
- Text or link post with a thumbnail
- One or more communities
- Comment
Lemmy rules the request is checked against
| Rule | What 1Post checks |
|---|---|
| Text limit | 10,000 characters, counted by code points |
| Media accepted | Images |
| Images per post | 1 |
| Threads | No |
| First comment | Yes |
| Posts per day, per connected account (1Post) | 20 |
The same table with sources is on the Lemmy specs page.
Lemmy options in the request
- First comment: add first_comment with text to an account object, and delay_min if it should wait.
Check the post before it is queued
Add "dry_run": true to test a post: nothing is kept, a valid one answers 200 and a broken one answers 422 naming the rule.
{
"error": {
"code": "invalid_for_platform",
"message": "lemmy refuses this post: Lemmy counts 10,032 of 10,000 characters in part 1. (text_too_long).",
"fix": "Fix the rule named in the message and send the post again.",
"retryable": false,
"request_id": "REQUEST_ID"
}
}An assistant connected to the MCP server sends the same fields to create_post; set one up.