general40
  • Vela NotificationsAPP2:41 PMPayment received, €2,400 from Acme Corp. Invoice #1042 is now marked as paid.
  • Marta Ruiz2:43 PMGreat, I'll close it out on the finance board.

Message

Ship your Slack integration in minutes, not months

Stop building a Slack app just to post a message. Zernio gives you one endpoint to schedule Slack messages and answer DMs and mentions, while we own the OAuth, the Events API server, and the token rotation.

Start for freeView API Docs
  • Channels
  • Threads
  • Files
  • DMs

Join 200,000+ of the world's most ambitious developers and builders

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Why Zernio vs Slack Web API?

Save 3-5 weeks of development time

Zernio API

  • Simple API key - start in 30 seconds

  • Automatic retries & queue management

  • Attach files to a post, we handle the upload

  • We run the Events API endpoint for you

  • One API for 17 platforms

Slack Web API Direct

  • Create a Slack app, manage scopes, handle re-auth on every scope change

  • Per-method rate limit tiers with your own backoff logic

  • Separate multi-step upload flow for files

  • Host an Events API endpoint with signature verification and 3s acks

  • Build separate integrations per platform

How It Works

Three steps to Slack automation

1

Profile

default

Slack

Connect your workspace

Install the Zernio app into your workspace with one OAuth click and pick the channel it publishes to.

2

POST /v1/posts

const { data } = await zernio.posts.createPost({
  body: {
    content: 'v2 is live 🚀',
    mediaItems: [{ url: 'https://cdn.acme.com/launch.jpg' }],
    platforms: [
      { platform: 'slack', accountId: 'acc_8f2a' },
    ],
    scheduledFor: '2027-01-15T14:30:00',
    timezone: 'Europe/Madrid',
  },
});

Build your integration

Use our simple REST API to schedule messages and files, or answer DMs and mentions. Same pattern works for all 17 platforms.

3

post.failed

Webhook sent to your app

Failed

Mon, 18 Jan

09:00, Europe/Madrid

Scheduled

v2 is live 🚀

Fri, 15 Jan at 14:30

Published

We handle the rest

Zernio publishes at your scheduled time, retries on failures, and notifies you via webhooks. You never touch Slack's API directly.

No Developer Portal setup, no Events API server to host, no signing secrets or token rotation to get right

Features

Everything you need to ship Slack features

Channels

Publish messages and upload files to a Slack channel.

Replies

Post inside an existing thread.

Identity

Override the bot's display name and avatar, or set a default for the channel.

Webhooks

Every incoming message tells you if your bot was mentioned, and which thread it's in.

DMs

Read and send DMs, and start one with any member of the workspace.

Emoji

React to a message, and get a webhook when someone reacts to yours.

Integrate

Three ways in. Same API behind all of them

Write it yourself with the SDKs, hand it to an agent over MCP, or run it from a shell.

Read the docs
import Zernio from '@zernio/node';
const zernio = new Zernio(); // reads ZERNIO_API_KEY
const { data: post } = await zernio.posts.createPost({
body: {
content: 'v2 is live 🚀',
mediaItems: [{ type: 'image', url: 'https://cdn.acme.com/launch.jpg' }],
platforms: [
{
platform: 'slack',
accountId: 'acc_xxx',
platformSpecificData: {
unfurlLinks: false,
username: 'Launch Bot',
},
},
],
publishNow: true,
},
});
And more
Supported Platforms

Build one integration
and reach 17 platforms with it

Frequently Asked Questions

Learn more

Slack Documentation

Scopes, fields and inbox behavior

Messaging API

Send and receive DMs programmatically

Posting API

Post, schedule and analyze content

Ship Slack today

No credit card, no sales call. Same reliability, 10x less code.

Start for free
  • SOC 2
  • GDPR compliant
  • 99.97% uptime
  • Under 50ms response