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HookNexus

GitHub Webhook Debugging Guide

GitHub can notify your systems about pushes, PRs, issues, and more. HookNexus is a convenient payload URL for development and debugging: you see headers, JSON body, and delivery history without deploying a public server first.

Prerequisites

  • Admin access to the repository (or organization) where you add the webhook
  • A HookNexus endpoint URL: https://api.hooknexus.com/h/{endpoint-id}

Repository webhook setup

  1. Open webhook settings

    On GitHub, open your repository → Settings → Webhooks → Add webhook.

  2. Set the payload URL

    https://api.hooknexus.com/h/YOUR_ENDPOINT_ID

  3. Set content type

    Select Content type: application/json (recommended for modern integrations).

  4. Choose a secret

    Enter a Secret string. GitHub uses it to compute X-Hub-Signature-256. Save the same value in your password manager—you need it to verify deliveries in your own application (see GitHub’s webhook documentation).

  5. Select events

    Choose Let me select individual events (or start with Just the push event for a minimal test).

  6. Create the webhook

    Click Add webhook. GitHub sends a ping event immediately if configured to do so—check HookNexus for the delivery.

Signed deliveries

GitHub sends:

  • Header: X-Hub-Signature-256
  • Format: sha256=<hex digest>
  • Algorithm: HMAC-SHA256 over the raw request body using your webhook secret

Validate deliveries in your server using the secret and GitHub’s documented procedure. HookNexus shows the raw body and headers so you can compare what you received with what your verifier expects.

Common events

EventTypical use
pushCI, deployments, changelog automation
pull_requestReview bots, merge queues
issuesIssue trackers, notifications
releaseRelease notes, artifact publishing

Start with one event type, confirm deliveries in HookNexus, then expand.

Organization webhooks vs repository webhooks

Repository webhookOrganization webhook
ScopeSingle repoAll repos in the org (per your selection)
Where to addRepo Settings → WebhooksOrg Settings → Webhooks
Use caseProject-specific automationOrg-wide policies, security scanning

Both use the same payload URL pattern and the same signing header format.

Troubleshooting

SymptomWhat to check
Red delivery in GitHubOpen the delivery; confirm URL reaches HookNexus (no corporate proxy blocking).
No X-Hub-Signature-256Webhook must use a secret; recreate if missing.
Signature invalidCompare secret character-for-character; verify raw body (no pretty-print changes).
Wrong repositoryFor org webhooks, confirm repo filters and event selections.