All twins

Resend

live · conformance passing

Models email delivery lifecycles, scheduled sends, domains, contacts, segments, broadcasts, pagination, idempotency, and API-key permissions.

Category
Email
Sandbox key
re_…
Verified against
resend 2.41.0, resend 6.24.0
Replaces
A live sending domain, hand-written email mocks

Scenarios

Start a sandbox in one of these, or describe the state you want in a sentence and the seeder writes the records it implies.

  • Hard bounce

    A recipient permanently rejects the message.

  • Spam complaint

    A delivered recipient marks the message as spam.

  • Delayed delivery

    A temporary failure delays delivery before it succeeds.

  • Suppressed contact

    A recipient is suppressed after a previous hard bounce.

  • Unverified sending domain

    Sending from the seeded domain is rejected.

  • Rate-limited API key

    Every request the operator's key makes is rate limited.

What it models

Records your code can read, write and edit for the life of the sandbox. A route the twin does not model returns a provider-shaped refusal rather than a plausible response.

  • emails
  • domains
  • api_keys
  • segments
  • audiences
  • contacts
  • broadcasts
  • idempotency_keys

Verified in CI against

  • pythonresend2.41.0
  • noderesend6.24.0

Live · console.twinbay.ai

Start with one base URL.

Create a sandbox, describe the state you want it in, and point your existing SDK at the hostname it gives you. The sandbox logs each request your agent makes, and you can edit any record it holds.

Start building

A sandbox in under a minute, no card required. Twinbay is free for academic researchers.