Upyo changelog

Version 0.3.0

Released on September 16, 2025.

@upyo/pool

• Added pool transport for combining multiple email providers with load balancing and failover strategies. [#8]

  • Added PoolTransport class with AsyncDisposable support.
  • Added PoolConfig interface.
  • Added ResolvedPoolConfig type.
  • Added TransportEntry interface.
  • Added ResolvedTransportEntry type.
  • Added PoolStrategy type for built-in strategies.
  • Added Strategy interface for custom routing logic.
  • Added TransportSelection interface.
  • Added RoundRobinStrategy class for equal distribution.
  • Added WeightedStrategy class for proportional distribution.
  • Added PriorityStrategy class for failover-based routing.
  • Added SelectorBasedStrategy class for content-based routing.
  • Support for round-robin, weighted, priority, and selector-based strategies.
  • Automatic failover and retry logic with configurable limits.
  • Comprehensive error aggregation across multiple providers.

@upyo/plunk

• Added Plunk transport. [#11]

  • Added PlunkTransport class.
  • Added PlunkConfig interface.
  • Added ResolvedPlunkConfig interface.
  • Added PlunkError interface.
  • Added PlunkResponse interface.
  • Support for both cloud-hosted and self-hosted Plunk instances.

@upyo/resend

• Added Resend transport. [#9]

  • Added ResendTransport class.
  • Added ResendConfig interface.
  • Added ResolvedResendConfig interface.
  • Added ResendApiError interface.
  • Added ResendBatchResponse interface.
  • Added ResendError interface.
  • Added ResendResponse interface.

Version 0.2.1

Released on August 4, 2025.

@upyo/smtp

• Fixed “Maximum call stack size exceeded” error when sending large attachments. [#6]

  The SMTP transport now uses Buffer.from().toString('base64') instead of the legacy btoa() function for base64 encoding, which resolves stack overflow issues with large attachments (e.g., 500KB+ files).

• Fixed UTF-8 encoding issue where email addresses were incorrectly encoded in SMTP headers. [#7]

  Only display names are now encoded using RFC 2047 encoding, while email addresses remain unencoded. For example, German ÄÖÜ <info@example.com> now correctly becomes =?UTF-8?B?...?= <info@example.com> instead of encoding the entire string including the email address.

Version 0.2.0

Released on July 17, 2025.

@upyo/core

• Improved type safety by making array fields readonly.

  • Changed the type of Message.recipients property from Address[] to readonly Address[].
  • Changed the type of Message.ccRecipients property from Address[] to readonly Address[].
  • Changed the type of Message.bccRecipients property from Address[] to readonly Address[].
  • Changed the type of Message.replyRecipients property from Address[] to readonly Address[].
  • Changed the type of Message.attachments property from Attachment[] to readonly Attachment[].
  • Changed the type of Message.tags property from string[] to readonly string[].

• Enhanced email address type safety with template literal types.

  • Added EmailAddress type.
  • Changed Address.address property type from string to EmailAddress.
  • Added isEmailAddress() type guard function for runtime email validation.

@upyo/ses

• Added Amazon SES transport. [#3]

  • Added SesTransport class.
  • Added SesConfig interface.
  • Added SesAuthentication interface.

@upyo/opentelemetry

• Added OpenTelemetry observability support. [#5]

  • Added OpenTelemetryTransport class.
  • Added OpenTelemetryConfig interface.
  • Added ObservabilityConfig interface.
  • Added MetricsConfig interface.
  • Added TracingConfig interface.
  • Added AttributeExtractor type.
  • Added ErrorClassifier type.
  • Added createErrorClassifier() function.
  • Added defaultErrorClassifier() function.
  • Added AutoConfig interface.
  • Added createOpenTelemetryTransport() function.
  • Added CreateOpenTelemetryTransportConfig interface.
  • Added createEmailAttributeExtractor() function.

Version 0.1.1

Released on July 14, 2025.

@upyo/smtp

• Fixed CJK character encoding corruption in SMTP transport HTML emails. Korean, Japanese, and Chinese characters are now properly encoded using UTF-8 quoted-printable encoding. [#4]

Version 0.1.0

Initial release. Released on July 13, 2025.