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JOB DETAILS

JavaScript Developer (Mid-Level)

CompanySipwise GmbH
LocationVienna
Work ModeOn Site
PostedOctober 30, 2026
About The Company
Sipwise develops and integrates highly-available and scalable telephony systems based on open-source software (and releases lots of its software as open-source). Our platforms are deployed at top-tier ISPs all over Europe, serving hundreds of thousands of customers each. We are an extremely dedicated team with a strong professional start-up culture reshaping the telecommunication market.
About the Role

Company Description

Sipwise develops Software Solutions that are among the most widely used in the Telco community and contribute significantly to industry-standard open-source SIP software. We also provide years of experience in developing and operating large-scale internet service platforms.

Job Description

We're looking for an experienced mid-level JavaScript Developer to help build and improve our products. You'll take ownership of features from requirements through to release, with the freedom to investigate problems, challenge requirements, and make technical decisions along the way.

You'll work closely with our Frontend Tech Lead, backend team and QA, with plenty of opportunity for discussion and collaboration when problems are complex or decisions have wider implications.

  • Build and Maintain: Deliver reliable, high-quality frontend features and fix bugs across our applications. You'll primarily work with Vue.
  • Maintain Engineering Standards: Write clean, maintainable code and add appropriate automated tests for the behaviour you're introducing or changing. Participate in constructive code reviews and contribute to architectural and technical discussions.
  • Own Your Work End-to-End: Take features and fixes through implementation, testing, and release, asking the right questions and investigating root causes to determine what actually needs to be done. Communicate early when you hit risks, uncertainty, or decisions that need wider input.
  • Refine Requirements: Review specs with a constructive eye, identifying missing information, technical constraints, gaps, edge cases, and opportunities for smoother user flows before writing code.
  • Collaborate Across Boundaries: Work with the backend team to align on shared best practices around API integration and data flow.

Qualifications

  • Professional experience building and maintaining production frontend applications.
  • Experience owning and delivering frontend features beyond simply implementing predefined tickets.
  • Proficiency with Git and version control best practices.
  • Strong core JavaScript fundamentals and sound engineering judgment.
  • Solid understanding of frontend architecture and the ability to make sensible technical decisions within your area of ownership.
  • Solid working knowledge of RESTful APIs and asynchronous data handling: comfortable reading API docs, spotting payload issues, and working constructively with backend engineers on data flow.
  • Experience with testing frameworks (Jest, Cypress etc.) and the ability to take responsibility for the testing and quality of your own work.
  • Demonstrated ability to navigate ambiguous requests, ask the right technical questions, and drive projects forward with autonomy.
  • Clear, concise communication skills across both technical and non-technical audiences.
  • Self-awareness, paired with a commitment to continuous learning.
  • Experience with Vue or any other modern frontend framework (React, Angular, etc.).
  • Experience with TypeScript.
  • Experience with Docker, Bash scripting, or other command-line tooling.

Additional Information

We don't expect you to have used every technology in our stack. Strong engineering and JavaScript fundamentals, problem-solving ability, and the capacity to learn unfamiliar technologies matter more than matching every item on the list.

We value open discussion, healthy technical debate, feedback, and shared ownership of the codebase. If you want a role where your judgment matters, where you're trusted to solve problems rather than just complete tickets, and your work is clearly yours, we think you'll like it here.

Depending on the country in which you would like to work, we offer you an employment contract or a contract for work and services.

  • Compensation: EUR 4000 - EUR 5000 - monthly
  • Key Skills
    JavaScriptVueTypeScriptGitRESTful APIsJestCypressDockerBashFrontend DevelopmentAutomated TestingCode ReviewSoftware ArchitectureAsynchronous Data Handling
    Categories
    TechnologySoftwareEngineering
    Job Information
    📋Core Responsibilities
    You will deliver high-quality frontend features using Vue and maintain engineering standards through clean code and automated testing. You will also collaborate with the backend team to align on API integration and data flow while taking ownership of features from requirements to release.
    📋Job Type
    contract
    💰Salary Range
    €4,000 - €5,000
    📊Experience Level
    2-5
    💼Company Size
    20
    📊Visa Sponsorship
    No
    💼Language
    English
    🏢Working Hours
    40 hours
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