Email on Acid

Email on Acid (now part of AWeber) provides client-rendering previews, accessibility checks, link validation, image and load-time analysis, spam testing, and a campaign precheck workflow. Direct competitor to Litmus with broadly similar coverage and typically lower entry pricing.

Judged purely as an API. What the request contract guarantees on retry, how complete the webhook event coverage is, whether suppressions are readable and writable programmatically, and how much the message log retains when something needs debugging in production.

Against high-frequency programmatic sends where a missed delivery is a product failure, Email on Acid covers none of the capabilities this audience leans on (idempotency keys, webhook coverage, event stream, the suppressions API, batch sending, and SDK breadth), so it fits only where those needs are genuinely absent.

• Idempotency keys: No
• Webhooks: No
• Event stream: No
• Operating since: Not published
• Suppressions API: No
• Best published rate per 1,000: Tiers not published in comparable form
• Batch sending: No
• SDKs: None
• Deliverability: Not applicable; preview and QA, not a sender.

Not applicable; preview and QA, not a sender.

Teams that want Litmus-grade previews at a lower entry price.

Teams already standardized on a sending platform with built-in previews.