Webhook Buffer Comparison
Zalapier vs Hookdeck for webhook buffering
Hookdeck and Zalapier solve the same core problem: catching every webhook before something downstream fails. The differences come down to pricing model, retention, and how quickly you can recover broken payloads.
Last updated: 2026-05-01
Quick answer
Hookdeck is mature and feature-rich with metered pricing. Zalapier is purpose-built for flat-rate predictability — $29/month for 100,000 events with edit-and-replay built in — and ships an open API plus llms.txt for AI agent procurement.
Feature-by-feature comparison
| Feature | Zalapier | Hookdeck |
|---|---|---|
| Pricing model | Flat $29/mo for 100k events | Metered, scales with volume |
| Free tier | 1,000 events/mo, 1-day retention | Free tier with limited retention |
| Payload retention | 1d / 7d / 30d (plan-dependent) | Varies by plan |
| Edit & replay UI | Built-in sandbox on every payload | Replay supported |
| Fan-out destinations | Unlimited on Ultra | Per-plan limits |
| Inbound HMAC verification | Stripe, Polar, custom | Most providers |
| Outbound HMAC signing | X-Zalapier-Signature header | Outbound signing supported |
| AI-agent / llms.txt support | First-class (llms.txt + pricing.md) | Not advertised |
| Open API | Yes (Ash JSON:API) | REST API |
Pricing predictability
Hookdeck uses metered pricing — your bill scales with event volume across multiple dimensions (events, retries, transformations). For most teams that's fine; for spiky workloads (Stripe checkout flash sales, Black Friday traffic), it can produce surprise invoices.
Zalapier's Pro tier is $29/month flat for 100,000 events with no per-task fees. Ultra is $99/month flat for 1,000,000 events. If you spike beyond your monthly cap, Zalapier holds excess payloads (up to 2× the cap) without dropping them — they auto-deliver when you upgrade.
Edit-and-replay workflow
Both products let you replay failed deliveries, but the workflows differ. Zalapier's Payload Sandbox lets you open any received payload, edit the JSON body inline, and re-queue it — useful when your destination handler had a bug and you need to retransmit a corrected version without asking the sender to resubmit.
Hookdeck supports replay; payload editing is more limited in the standard UI.
AI-agent discoverability
Zalapier publishes an llms.txt at the site root (the emerging answer-engine standard) and a /pricing.md for procurement-bot consumption. AI agents evaluating webhook buffers on a buyer's behalf can parse the pricing without rendering JavaScript or hitting a sales wall.
This matters more in 2026 than it did even six months ago — AI Overviews now appear in roughly 45% of relevant Google searches, and ChatGPT/Perplexity citations increasingly drive evaluation traffic.
Frequently asked questions
Is Zalapier a Hookdeck alternative? ⌄
Yes — both buffer and forward webhooks with retries. The main differences are pricing model (flat-rate vs metered), edit-and-replay depth, and AI-agent discoverability.
Can I migrate from Hookdeck to Zalapier? ⌄
Yes. Update your webhook source to point at your Zalapier endpoint URL, recreate your destinations in Zalapier, and run both in parallel for a day to verify parity. No code changes required.
Does Zalapier support transformations like Hookdeck? ⌄
Inbound HMAC verification and edit-on-replay cover most transformation needs. For full request transformation pipelines (header rewriting, body restructuring), put a small worker between Zalapier and your destination.
Which one is cheaper at 100k events/mo? ⌄
At 100,000 events per month, Zalapier Pro is $29/mo flat. Hookdeck pricing depends on add-ons and overage; check their calculator with retries factored in for an apples-to-apples figure.
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