Testing

Email on Acid

Email previews and pre-deployment QA across 90+ clients.

See alternatives ↗ Visit emailonacid.com ↗

overview

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.

for teams building autonomous agents

An agent stack treats email as a two-way primitive. Inbound has to arrive as structured JSON a tool call can consume, sends have to be safe to retry when a model loop repeats itself, and every action needs an audit trail. A provider without inbound parsing only solves half the problem.

Against inbound parsing into tool calls and model-generated sends that must not duplicate, Email on Acid covers multi-tenant support, and does not cover inbound parsing, idempotency keys, webhook coverage, event stream, batch sending, and SDK breadth. Whether that gap matters depends on how central those are to the build.

Inbound parsing: No
Idempotency keys: No
Webhooks: No
Operating since: Not published
Event stream: No
Best published rate per 1,000: Tiers not published in comparable form
Batch sending: No
SDKs: None
Multi-tenant: Yes

deliverability

Not applicable; preview and QA, not a sender.

best for

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

not great for

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

pros

› 90+ client previews including legacy Outlook and major mobile environments
› Campaign precheck bundles rendering, accessibility, links, and spam in one report
› Generally cheaper entry point than Litmus

cons

› Builder and analytics are less polished than Litmus
› AWeber acquisition introduces some uncertainty about long-term roadmap
› API surface is narrower than Litmus

Features at a glance

API	Yes
SMTP	No
SDKs	None
Webhooks	No
Templates	basic
React Email	No
Batch send	No
Scheduled send	No
Suppressions	No
Multi-tenant	Yes
Inbound parsing	No
Event stream	No
Idempotency keys	No
Dedicated IP	No

Appears in rankings

#02 →

5 Best Email Client Preview and Testing Tools (2026), Tested

Closest direct competitor to Litmus with broadly similar preview coverage. Generally cheaper entry price; campaign precheck bundles rendering, accessibility, links, and spam in one report.