A Native ASN.1 Workbench for macOS

ASN.1 works quietly beneath technologies such as X.509 certificates, wireless communications, network-management protocols, and authentication systems. After years of working with X.509 and wireless protocols, industry experts kept encountering the same practical need: quickly verify a packet, inspect an encoding, or construct compliant data for testing. These tasks were too small to justify writing a new program, but disruptive enough to interrupt the work.

Ideally, the solution should be something like a calculator app but for ASN.1: a tool that stays close at hand, opens quickly, answers the immediate question, and lets you continue working.

That idea became ASN1, a native macOS workspace that keeps schemas, JSON values, encoded payloads, and diagnostics together. It supports writing and validating ASN.1 schemas; encoding and decoding BER, DER, OER, PER, UPER, and XER; GSER encoding; and visual inspection of BER and DER structures. Processing takes place locally on the Mac.

The ASN.1 language is valuable because it separates the definition of data from the mechanics of its encoding. Once the schema and tooling are in place, developers can work with defined structures rather than repeatedly creating custom parsers. The ASN1 app aims to make that workflow more immediate and approachable for Mac users, especially during the development and tinkering phases. The app is available for free on the Mac App Store, with an optional one-time Pro unlock for advanced features.

Website: https://asn1.inyosystems.com/

Mac App Store: https://apps.apple.com/us/app/asn1/id6477905565