PostOnce
DocsChatGPTGrokCursorClaudeMCP

Grok

Add PostOnce in Grok

This page is for people who use Grok in the browser or the Grok Bot plugin and want PostOnce in the conversation. Connected means Grok opened a PostOnce Allow screen in the browser and you approved it. After that, Grok can list the social accounts already on your workspace and save unscheduled drafts. It waits for a yes before publish or schedule. Never paste passwords, 2FA codes, refresh tokens, or API keys into the chat.

MCP URL for grok.com

Use this on grok.com/connectors. Streamable HTTP. Grok should open the browser for OAuth.

https://postonce.app/api/mcp

How to add it on grok.com

  1. Open grok.com/connectors. PostOnce is not in the built-in catalog, so do not hunt for a branded tile.
  2. Click New Connector, then Custom.
  3. Name it PostOnce if Grok asks for a label. Paste the public MCP URL above, including /api/mcp.
  4. Complete authentication. Sign in to PostOnce if a browser window opens, then hit Allow.

Grok labels move. If you see + Add Connector or Other instead of New Connector → Custom, it is the same paste. The server URL does not change.

On Grok Business or Enterprise, a team admin has to provision the connector in console.x.ai (Grok Business → Connectors) before members can connect it on grok.com. A custom connector that will not save is often the URL without /api/mcp, or a sign-in that was closed before Allow.

Grok Bot plugin

If you opened us from grokbot.dev/plugins/postonce, paste this referral URL only. First Allow on that URL is a month free. Same tools and the same draft-first rule.

https://postonce.app/api/mcp?ref=grokbot

grok.com should keep the public URL without ?ref=grokbot. Mix the two and you still reach the same server; the free month is tied to the plugin referral.

After you connect

Ask Grok to list your PostOnce accounts first. Then ask for an unscheduled draft, read the copy and the targets, and say yes only when you want it scheduled or published. If Instagram or TikTok is missing, Grok should send you to postonce.app/accounts and stop. Those networks need provider consent in the PostOnce dashboard. Grok must not ask for passwords, 2FA codes, refresh tokens, or API keys in the chat. Hosted MCP can pull a public image or video URL onto the PostOnce CDN; files dropped into the Grok chat still cannot.

Prompts that work in Grok

Use these after the connector shows as connected. Say no if Grok offers to publish.

  • “Use the PostOnce connector. List the social accounts already connected to my workspace.”
  • “Who am I on PostOnce, and which plan is this workspace on?”
  • “Save an unscheduled PostOnce draft that says “Saturday market, 9 to 1, Northside stall 12” for an Instagram account I already connected. Do not publish and do not schedule.”
  • “Read back that draft and the targets. Leave it unpublished.”

Price

PostOnce Solo is €15/month, or €12/month billed yearly (€144/yr). Pro is €30/month, or €25/month billed yearly (€300/yr). Those are VAT-inclusive list prices: no per-channel fee, no free plan, and signup is Lemon checkout.

Buffer Essentials is $6 per channel monthly, or $5 per channel if billed yearly, so five connected accounts is $30/month on monthly Buffer ($25/month effective yearly). Post Bridge's public Creator plan is $29/month for 15 connected accounts. Solo at €15/month sits against Post Bridge Creator at $29/month, and against Buffer at $30/month for five channels. Those figures are EUR and USD as published.

PostOnce pricing

Other clients

Same server for ChatGPT, Cursor, and Claude. Technical fields live on the MCP connect page.

Stuck? Email [email protected]. Privacy · Terms

Lucro Limited, Ireland. Company no. 811725.

Questions: [email protected]

DocsChatGPTGrokCursorClaudeMCPPrivacyTerms