caldays vs Guerrilla Mail
Same instrument, two spec sheets — measured, not claimed.
caldays vs Guerrilla Mail: common questions
Which is more reliable, caldays or Guerrilla Mail?
On our scheduled checks, caldays leads on measured uptime — caldays at 100% versus Guerrilla Mail at 95.1% over 90 days. These are our own probe results, not provider claims; the uptime bars above show the day-by-day record for both.
Which is faster, caldays or Guerrilla Mail?
caldays has the lower median latency in our checks — caldays responds in 149 ms versus Guerrilla Mail at 298 ms (P50). Tail latency (P95) is in the table above; for most workloads the median is the number that shapes how the API feels.
Do caldays and Guerrilla Mail need an API key?
Neither needs a paid key — caldays is callable with no signup, and Guerrilla Mail is callable with no signup. Both are quick to prototype with; rate limits still apply.
Can I call caldays and Guerrilla Mail from the browser?
Yes — both caldays and Guerrilla Mail send CORS headers over HTTPS, so front-end code can fetch either directly with no backend proxy. That makes them easy to swap in a client-side app while you compare responses.
Are caldays and Guerrilla Mail free for commercial use?
caldays has unclear commercial terms, and Guerrilla Mail has unclear commercial terms. We track service terms and the data license as separate fields — see the Commercial use and Data license rows above, and confirm both before shipping either in a paid product.