What is Tecken?

Tecken is an umbrella project consisting of two services:

  1. Mozilla Symbols Server which manages symbols generated by builds of Mozilla products (upload, download).

  2. Mozilla Symbolication Server which has a symbolication API for converting memory addresses into symbols (symbolication).


Rough architecture diagram of Tecken:

Tecken architecture diagram

Important services in the diagram:

  • Symbols service (aka symbols.mozilla.org):

    Host: https://symbols.mozilla.org/

    The symbols webapp handles upload and download of symbols.

    • upload: The webapp handles incoming uploads with the upload API. It manages upload permissions and bookkeeping of what was uploaded, by whom, and when. It exposes an interface for debugging symbol upload problems.

    • download: The webapp handles download API requests by finding the symbol file in one of the AWS S3 buckets and returning an HTTP redirect to the final location.


    The Symbols service also has a symbolication API. This version of the symbolication API is deprecated. Please switch to using the Symbolication service at https://symbolication.services.mozilla.com/ instead.

    Code is in the tecken subdirectory.

  • Sybmolication service (aka symbolication.services.mozilla.com):

    Host: https://symbolication.services.mozilla.com/

    The symbolication webapp is a symbolication API microservice that uses the Symbolic library to parse SYM files and do symbol lookups.

    Code is in the eliot-service subdirectory.

Repository structure

Here’s a bunch of top-level directories and what’s in them:

bin/                    -- scripts for running and developing
docker/                 -- Dockerfile and image building bits
docs/                   -- documentation
favicons/               -- favicons used by Symbols webapp
frontend/               -- Symbols webapp JS frontend
schemas/                -- API schemas

These directories have test stuff in them:

systemtests/            -- systemtests for Symbolication and Symbols services

These directories hold code for the Tecken webapp service and the Eliot symbolication service:

eliot-service/          -- Symbolication service unit tests and code (Eliot)
tecken/                 -- Symbols service unit tests and code


Originally, there was just Tecken which handled upload, download, and symbolication. Then we split symbolication into a separate service codenamed Eliot 1.

Now “Tecken” refers to the overall project covering both the Mozilla Symbols and Mozilla Symbolication services. But in the code “tecken” refers to Mozilla Symbols service and “eliot” refers to the Mozilla Symbolication service.


Tecken Symoblication -> TS Eliot.