How to Send Form Submissions to Slack

Why send forms to Slack

For an agency, a B2B SaaS team, or any business that runs in Slack all day, every email notification is a context switch. The lead goes to your inbox, you forward it to the team channel, someone responds 20 minutes later. By then the prospect has already filled out the same form on a competitor's site.

Slack-native delivery cuts that loop to seconds. The notification lands in #leads with the prospect's name, email, message, source, and a button to reply. Your team responds in-thread, marks it with a reaction when handled, and the channel becomes a working pipeline. splitforms ships Slack-formatted messages out of the box — no custom payload required.

Step 1 — Create the Slack webhook

Slack split webhooks into "Apps" in 2020, so the path is two steps deep but still under three minutes:

1. Go to api.slack.com/apps and click Create New App → From scratch.
2. Name it (e.g. "splitforms"), pick your workspace, click Create.
3. In the left sidebar click Incoming Webhooks, toggle Activate Incoming Webhooks to On.
4. Scroll down, click Add New Webhook to Workspace.
5. Pick the destination channel (e.g. #leads) and click Allow.
6. Copy the webhook URL. It looks like https://hooks.slack.com/services/T0/B0/abcXYZ....

That URL is the only credential you need. Anyone holding it can post to the channel as your app — store it as a secret. If it leaks you can rotate by clicking the trash icon next to the webhook in the same screen and adding a new one.

Step 2 — Connect it to splitforms

In your splitforms dashboard open the form, click Webhooks → Add, choose the Slack integration type, and paste the URL.

Webhook URL: https://hooks.slack.com/services/T0/B0/abcXYZ...
Type:        Slack (auto-formats as Block Kit)
Events:      submission.created

Click Send test event. A formatted message lands in the channel within ~250ms with header, sender info, and message body. Submit a real form to confirm end-to-end.

Wiring it programmatically (Terraform, CI, an admin script) hits the same endpoint:

curl -X POST https://splitforms.com/api/forms/frm_5fK9.../webhooks \
  -H "Authorization: Bearer YOUR_ACCESS_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://hooks.slack.com/services/T0/B0/abcXYZ",
    "type": "slack",
    "events": ["submission.created"]
  }'

Block Kit: the Slack payload, explained

Slack's message format is called Block Kit. A "message" is a top-level text string (used as the notification preview and as accessibility fallback) plus a blocks array of layout blocks. The blocks you care about for form notifications are header, section, divider, and context.

POST https://hooks.slack.com/services/T0/B0/...
Content-Type: application/json

{
  "text": "New submission from Ada Lovelace",
  "blocks": [
    {
      "type": "header",
      "text": { "type": "plain_text", "text": "📬 New contact form submission" }
    },
    {
      "type": "section",
      "fields": [
        { "type": "mrkdwn", "text": "*Name:*\nAda Lovelace" },
        { "type": "mrkdwn", "text": "*Email:*\n<mailto:ada@example.com|ada@example.com>" },
        { "type": "mrkdwn", "text": "*Source:*\nhomepage" },
        { "type": "mrkdwn", "text": "*Spam score:*\n0.02" }
      ]
    },
    {
      "type": "section",
      "text": { "type": "mrkdwn", "text": "*Message*\n>>> Hi — testing the Slack pipeline." }
    },
    {
      "type": "context",
      "elements": [
        { "type": "mrkdwn", "text": "<https://splitforms.com/dashboard/submissions/sub_abc|Open in splitforms ↗>" }
      ]
    }
  ]
}

splitforms generates this automatically when you pick the Slack type. The section-with-fields pattern renders as a two-column grid on desktop and stacks on mobile — perfect for form fields. The >>>at the start of the message body is Slack's blockquote markdown, which makes long submissions render with a colored left border.

Want a different layout? splitforms accepts a custom Block Kit template per webhook, with the same {{ fields.name }} Mustache syntax used elsewhere in the dashboard. Build the layout with Slack's Block Kit Builder at app.slack.com/block-kit-builder, paste the JSON in, and replace literal values with template variables.

Channel routing: one form, many channels

Real teams want different forms — or different submissions to the same form — going to different channels. Three common patterns:

• One form, multiple channels. Add multiple Slack webhooks to the form. Each posts in parallel. Common for fan-out: #leads for the team, #audit for the archive, #urgent if a priority field is set.
• Conditional routing by field. Set a webhook condition like fields.deal_size == "enterprise" in the splitforms dashboard. Only matching submissions trigger that delivery. Pair with a second condition for fields.deal_size != "enterprise" to split the firehose.
• Form per channel. If the forms are genuinely different (sales contact vs support ticket vs careers), create separate splitforms forms with separate access keys, each with its own Slack webhook. Cleaner audit trail and you can scope spam settings per form.

See the lead notifications use case for the conditional routing config and the splitforms docs for the full Block Kit template reference.

Cost comparison vs Zapier and Make

The reason this post exists at all is that "Webhook → Slack" is a $50/mo line item if you go via a no-code tool. Here's the math at 2,000 form submissions per month — a realistic volume for a modest B2B contact form:

At 2k submissions/month splitforms native is $44/mo cheaper than Zapier and significantly faster (one HTTP hop instead of two). The splitforms 4-year plan ($59 one-time, 15,000 submissions/month for 48 months) makes the math even better at higher volume — Zapier still scales linearly with task count.

The Zapier path makes sense if you already have a complex Zap with branching logic. For straight "form to Slack", native is the obviously correct choice. See pricing for the full tier breakdown.

Mentions, threads, and reactions

For a high-priority form (sales demo request, support escalation), an inline @-mention in the Block Kit message gets a real human attention faster than a notification badge:

{
  "text": "Sales demo requested",
  "blocks": [
    {
      "type": "section",
      "text": {
        "type": "mrkdwn",
        "text": "<!subteam^S012ABCDEF> demo request from {{ fields.company }}"
      }
    },
    { /* ...rest of the form fields... */ }
  ]
}

S012ABCDEF is the user-group ID for, say, @sales-team. Get it from Slack → People & user groups → user group → Copy member ID. For an individual person use <@U01ABCD2EFG>with the user's member ID.

Two team conventions worth adopting:

• Reply in-thread, not in the channel.Slack's threading keeps the form's "conversation" (your reply, internal discussion, "closed: customer churned") attached to the original submission. The channel stays scannable.
• Use a reaction emoji to mark handled. 👀 = looking at it, ✅ = responded, 🗄️ = archived. Cheap, visible, no separate tool.

For more advanced workflows — auto-creating a thread per submission, tagging by source, posting to a private channel and a public one in parallel — see the webhook reference.

Tech support and troubleshooting

The five Slack webhook issues we see most often:

• Slack returns invalid_payload — JSON shape is malformed or a block is missing a required field. Validate the payload in Block Kit Builder first, then re-paste into splitforms.
• channel_not_found — The webhook channel was archived or the app was removed. Recreate the webhook from api.slack.com/apps and update the URL.
• @mentions render as plain text — Slack expects user IDs (<@U01...>) and group IDs (<!subteam^S01...>), not handles. Right-click in Slack > Copy member ID for the correct format.
• Message arrives slowly — Slack rate-limits ~1 msg/sec per webhook. splitforms backs off automatically; if you're hammering it, fan out to additional webhooks instead of one.
• Free workspace history disappears — Slack free workspaces hide messages older than 90 days. Add a second destination (email, Notion, Google Sheets) for long-term archive.

The full webhook spec, retry policy, and HMAC signature are in the splitforms docs and the API reference. Plan and billing questions live in the splitforms FAQ.

FAQ

Next steps

• Add a Discord destination beside Slack — Send form submissions to Discord.
• Persist leads to a database — Airtable or Notion.
• Sign every webhook with HMAC — webhook security guide.
• Compare splitforms vs the legacy options — splitforms vs Formspree.