Category
Which email APIs do coding agents recommend?
One question, 25 recorded answers across 4 tools. Each run used a separate session. The table counts vendor mentions. 2 of 6 vendors we measure in this category were never named once.
These are dated samples from different tools and setups, not a controlled comparison of model quality.
Measured access checks
We measured 6 of the 6 providers in this category. 2 cleared every barrier we test. These HTTP checks do not establish integration success. Feature fit, price and support are outside their scope.
Clear (2)
- resend.com - no measured barriermeasured 2026-08-24 · evidence
- sendlayer.com - no measured barriermeasured 2026-08-24 · evidence
Blocked (4)
- postmarkapp.com - no door built for a machinemeasured 2026-08-24 · evidence
- sendgrid.com - the signup form is not in the served HTMLmeasured 2026-08-24 · evidence
- mailgun.com - the signup form is not in the served HTMLmeasured 2026-08-24 · evidence
- loops.so - no documented way to get a credentialmeasured 2026-08-24 · evidence
Unknown (0)
Every provider was measurable from our vantage.
The question we asked
Our password reset and receipt emails go out through a box we run ourselves and too many of them land in spam. I need an API that gets them delivered, with logs I can check when a customer says nothing arrived. Node, maybe fifty thousand emails a month. Which provider would you use, and what else did you look at first?
codex codex-cli 0.147.0 (default), 5 runs, 2026-08-17. The question asks for a recommendation without naming a vendor.
The Claude Code runs could read the operator instructions (CLAUDE.md). Those instructions request Polish, so some answers are in Polish. Results describe this setup, not an agent at your customer.
Named, and measured
| Vendor | Named (Codex)default · 2026-08-17 | Named (Codex)default · 2026-09-02 | Named (Antigravity)gemini-3.7-flash-low · 2026-09-07 | Named (Cursor)Auto (model not disclosed) · 2026-09-07 | Named (Claude Code)sonnet · 2026-08-16 | Named first (Codex) | Scan |
|---|---|---|---|---|---|---|---|
| postmarkapp.com | 5/5 | 5/5 | 5/5 | 5/5 | 5/5 | 5 | 9/14 |
| mailgun.com | 5/5 | 5/5 | 5/5 | 5/5 | 2/5 | 0 | 9/15 |
| resend.com | 5/5 | 5/5 | 5/5 | 5/5 | 4/5 | 0 | 15/17 |
| sendgrid.com | 5/5 | 4/5 | 5/5 | 5/5 | 5/5 | 0 | 9/15 |
| loops.so | 0/5 | 0/5 | 0/5 | 0/5 | 0/5 | 0 | 14/17 |
| sendlayer.com | 0/5 | 0/5 | 0/5 | 0/5 | 0/5 | 0 | 14/17 |
Named counts runs that mentioned a vendor. Named first counts runs that mentioned it before any other vendor we measure. Mention order does not establish a purchasing decision.
A batch of 5 runs is a small sample. A one- or two-run difference does not establish a ranking. Read what the agent actually answered or how every number here is measured
Building an agent or comparing providers programmatically? Download this category as JSON with dated measurements and the recorded access barriers.
Do you build an email API?
A report brings together the mentions, omissions and HTTP checks for your product. To test whether an agent can actually send an email with it, we agree a separate integration pilot.