LITSLINK

We are actively looking for a results-driven Sales Manager with strong UpWork experience to strengthen our sales team at LITSLINK. This role is perfect for someone who is passionate about IT, understands how to build long-term relationships with clients, and thrives in a fast-paced, dynamic environment.

If you’re skilled at closing deals, building trust, and navigating the UpWork platform with confidence — let’s connect!

Qualifications

• Successful experience in Software Development service sales

• Strong desire to work hard and achieve ambitious goals; result-oriented mindset

• Ability to build commercial proposals, present company USP, and deliver persuasive pitches

• Experience writing high-converting proposals

• Proven expertise in managing and optimizing UpWork company profiles

• Solid understanding of Web/Mobile development technologies and tech stacks

• Knowledge of SDLC and Software Project Management

• Experience with project estimations and validating requirements

• Ability to gather and clarify business requirements during pre-sale phase

• Excellent communication and commercial negotiation skills

• Upper-Intermediate or Advanced English level

• Positive and professional attitude

• Ability to position the company’s value proposition and work autonomously

Will be a plus:

• Prior experience in UpWork sales

• Technical background in software development

• Familiarity with HubSpot and Jira

Key Responsibilities

• Sell software development & UX/UI design services via the UpWork platform

• Write persuasive proposals, negotiate with leads and clients

• Meet and exceed sales KPIs for new and existing clients

• Manage client expectations and propose optimal solutions

• Collect and discuss business requirements, handle estimations

• Resolve escalations and maintain smooth client relationships

• Collaborate with PMs and technical teams

• Suggest improvements to sales processes and activities

• Boost sales within ongoing projects while ensuring high client satisfaction

• Maintain excellent feedback rates on platforms like UpWork, Clutch, GoodFirms

• Develop, review, and improve sales standards, guides, templates, and proposal materials

• Provide regular reporting (weekly, monthly, quarterly, annually) on sales activity and results

What We Offer

• Competitive base salary and attractive sales commission plan

• Remote-first culture

• Full support from our experienced architectural board and implementation teams

• Educational opportunities and professional development

• English lessons

What happens after you apply:

• We review your application and contact you to set up a quick call with one of our recruiters

• Interview with the Head of Department

• Proposal for cooperation

Ready to join a team where your impact matters? Apply now and let’s build something great together.

LITSLINK is looking for a motivated Junior Sales Manager who wants to grow in IT service sales and work with international clients via UpWork. This role is ideal for someone at the start of a sales career with strong communication skills and a desire to learn.

Requirements
• Interest in IT & software development services
• English — Intermediate+ (written & spoken)
• Strong written communication skills
• Willingness to learn sales processes and work towards KPIs
• Responsibility, proactivity, and result-oriented mindset
• Basic understanding of B2B sales or client communication

Nice to have
• Any experience with UpWork
• Experience in sales, lead generation, or customer support
• Basic understanding of web or mobile development
• Knowledge of SDLC
• Experience with CRM tools (HubSpot, Pipedrive, etc.)

Responsibilities
• Assist in selling software development & UX/UI services via UpWork
• Help write proposals and communicate with leads
• Qualify incoming requests and collect initial requirements
• Support pre-sales activities and follow-ups
• Maintain CRM and sales reports
• Learn estimation and deal-closing processes
• Follow internal sales processes and templates

We offer
• Full-time position with growth to Middle Sales Manager
• Competitive salary + bonuses
• Mentorship and structured onboarding
• Remote-first work format
• English lessons
• Clear processes and supportive team

Hiring process
• Recruiter interview
• Interview with Head of Sales
• Offer

About the Role

We are urgently looking for a Senior Python Backend Engineer to join a Client’s team and help scale backend services and AI-driven systems. This role is for someone who can quickly jump into production work, take ownership, and deliver impact in a fast-moving environment.

Location: Remote
Cooperation Type: Full-time, long-term
Experience Level: 7+ years
Start: ASAP

Responsibilities

• Design, develop, and maintain backend services using Python and FastAPI
• Build production-grade APIs for data ingestion, processing, and ML/LLM inference
• Work with high-volume structured and unstructured data (text, documents, embeddings, events)
• Build asynchronous and event-driven systems (RabbitMQ or similar)
• Design and optimize PostgreSQL schemas and queries for performance and reliability
• Support AI/ML and LLM model serving in production
• Build and maintain data and AI pipelines
• Ensure system performance, reliability, and scalability
• Debug production issues and contribute to continuous improvement
• Collaborate with Product, ML, and Frontend teams
• Write clean, maintainable, and well-documented code

Requirements

• 7+ years of backend engineering experience with Python
• Strong hands-on experience with FastAPI (or Flask / Django REST)
• Solid understanding of RESTful API design, auth, and security
• Strong experience with PostgreSQL (indexes, optimization, concurrency)
• Experience with message queues (RabbitMQ or similar)
• Experience with data pipelines and processing large datasets
• Exposure to AI/ML or LLM-powered systems (production or near-production)
• Experience with Docker and CI/CD
• Ability to start quickly and work independently
• English: Intermediate or higher

Nice to Have

• Experience with vector databases
• Kubernetes or container orchestration
• Experience with ETL / ELT pipelines
• Experience with GPU / compute-heavy workloads

What We Offer

• Competitive compensation based on experience (gross system)
• Fully remote cooperation
• Fast hiring process and quick start
• Opportunity to work on a real AI product with immediate impact
• Direct collaboration with a client’s engineering team

What happens after you apply

• Quick CV review
• Short recruiter call
• Technical interview with LITSLINK team & technical meeting with the Client
• Fast decision & offer

About the Role

We are looking for a Secure Mobile Engineer (Flutter) to join a Client’s team building a Zero-Knowledge mobile product.
This role is security-critical: the mobile app handles encryption, key management, and sensitive data locally — meaning client-side security is the core of the system.

👉 Our priority is a Senior-level engineer, but we are also open to strong Middle candidates with solid security fundamentals and growth potential.

Location: Remote
Cooperation Type: Full-time, long-term
Experience Level: Senior / Middle
Start: ASAP

Responsibilities

• Design, develop, and maintain a secure Flutter mobile application (iOS & Android)
• Implement client-side encryption, key generation, and secure session handling
• Work with Swift / Kotlin via platform channels
• Implement secure local storage using iOS Keychain, Android Keystore, and encrypted SQLite (SQLCipher)
• Apply memory hygiene practices to prevent sensitive data leaks
• Implement certificate pinning and protect against MITM attacks
• Build privacy-first features aligned with Zero-Knowledge security principles
• Work on on-device processing and AI features (offline inference where applicable)
• Collaborate with backend and security teams to ensure end-to-end system security
• Participate in architecture discussions and security reviews
• Write clean, testable, and well-documented code

Requirements

• 4+ years of mobile development experience with Flutter / Dart
• Strong hands-on experience with Flutter in production apps
• Experience with mobile security and secure data handling
• Understanding of applied cryptography and encryption principles
• Experience with iOS Keychain and Android Keystore
• Experience implementing secure local storage (SQLCipher / encrypted SQLite)
• Experience working with Swift and Kotlin via platform channels
• Experience with state management (BLoC or Riverpod)
• Experience implementing certificate pinning and network security
• Ability to work on security-critical features and privacy-first systems
• English: Intermediate or higher

Nice to Have

• Experience with Signal Protocol or MLS
• Experience with Zero-Knowledge systems
• Experience with on-device AI (TensorFlow Lite, MediaPipe, on-device LLMs)
• Experience with Tor / Orbot or anonymous routing
• Experience with advanced mobile OS security or threat modeling

What We Offer

• Competitive compensation according to your experience (gross system)
• Fully remote work and long-term cooperation
• Opportunity to work on a high-security, privacy-first product
• Direct impact on core security architecture
• Fast hiring process and quick start
• Supportive engineering culture focused on quality, ownership, and security

What happens after you apply

• Quick CV review
• Short recruiter call
• Technical interview with LITSLINK team
• Fast decision & offer

About the Role

We are looking for a Senior Backend Engineer (Java) to join a Client’s team building a Zero-Knowledge, privacy-first backend.

This role focuses on cryptography, encrypted data transmission, secure APIs, and privacy-preserving system design.

Your mission is to ensure that data is encrypted, metadata is minimized, and sensitive information is never exposed.

Location: Remote
Cooperation Type: Full-time, long-term
Experience Level: Senior, Middle (2 positions) 
Start: ASAP

Responsibilities

• Design and develop secure backend services using Java and Spring Boot
• Implement end-to-end encrypted APIs and secure data transport
• Build cryptography-driven systems for secure messaging and data exchange
• Design secure key management and authentication mechanisms
• Protect data in transit using strong encryption and secure protocols
• Reduce metadata exposure and enforce privacy-first architecture
• Work with PostgreSQL / Redis / distributed systems in secure contexts
• Implement high-load, scalable, and security-hardened services
• Participate in threat modeling, security reviews, and architecture decisions
• Collaborate with mobile, cryptography, and DevSecOps teams

Requirements

• 6+ years of backend engineering experience
• Strong experience with Java and Spring Boot
• Solid understanding of applied cryptography and encryption
• Experience building secure APIs and encrypted data pipelines
• Experience with secure communication protocols (HTTPS, WebSockets, gRPC, encrypted messaging)
• Experience with key management, session security, and auth flows
• Strong experience with PostgreSQL and high-load systems
• Experience designing privacy-first or security-sensitive architectures
• English: Upper-Intermediate or higher

Nice to Have

• Experience with Zero-Knowledge architectures
• Experience with Signal Protocol / MLS / secure messaging
• Experience with Cassandra / ScyllaDB / Redis
• Experience with metadata minimization / privacy engineering
• Experience with threat modeling / security architecture
• Experience with DevSecOps / hardened infrastructure

What We Offer

• Competitive compensation according to your experience (gross system)
• Fully remote work and long-term cooperation
• Opportunity to work on a privacy-first, security-critical product
• Ownership over core backend systems and architecture
• Fast hiring process and quick start
• Supportive engineering culture focused on quality, ownership, and impact

What happens after you apply

• Quick CV review
• Short recruiter call
• Technical interview with LITSLINK team 
• Fast decision & offer

About the Role

We are looking for a Senior DevSecOps / Infrastructure Engineer to join a Client’s team building a privacy-first, Zero-Knowledge product.
This role focuses on security, hardened infrastructure, immutable deployments, and verifiable CI/CD pipelines. The goal is to ensure the system is tamper-resistant, privacy-preserving, and secure by design.

Location: Remote
Cooperation Type: Full-time, long-term
Experience Level: Senior
Start: ASAP

Responsibilities

• Design, build, and maintain secure cloud or bare-metal infrastructure
• Implement and manage Docker and Kubernetes with strict network policies
• Manage Infrastructure as Code using Terraform or Ansible
• Harden systems using SELinux, AppArmor, OS hardening, and minimal attack surface practices
• Implement immutable infrastructure (replace servers instead of patching)
• Set up and manage secrets management solutions (Vault / KMS / HSM)
• Build and maintain secure CI/CD pipelines with reproducible and verifiable builds
• Implement monitoring and observability using Prometheus and Grafana (zero-log approach where possible)
• Work on traffic obfuscation and privacy-preserving networking
• Collaborate with backend, mobile, and security teams to ensure end-to-end system security
• Participate in architecture decisions, security reviews, and incident prevention
• Ensure high availability, reliability, and scalability of infrastructure

Requirements

• 6+ years of experience in DevSecOps / Infrastructure Engineering
• Strong experience with Linux server administration and hardening
• Hands-on experience with Docker in production environments
• Strong experience with Kubernetes (networking, security, scaling)
• Experience with Infrastructure as Code (Terraform or Ansible)
• Experience with cloud platforms (AWS or GCP)
• Experience building and maintaining CI/CD pipelines
• Experience with secrets management (Vault, KMS, or HSM)
• Experience with monitoring and observability (Prometheus, Grafana)
• Strong understanding of infrastructure security, threat modeling, and risk mitigation
• Ability to work independently and take ownership of critical infrastructure components
• English: Upper-Intermediate or higher

Nice to Have

• Experience with Immutable Infrastructure
• Experience with Reproducible / Verifiable Builds
• Experience with HashiCorp Vault
• Experience with Hardware Security Modules (HSM)
• Experience with traffic obfuscation or privacy-focused networking
• Experience with bare metal or privacy-focused hosting (Hetzner, Swiss hosts)
• Experience with zero-log monitoring practices
• Experience with privacy-first or security-critical products

What We Offer

• Competitive compensation according to your experience (gross system)
• Fully remote work and long-term cooperation
• Opportunity to work on a security-critical, privacy-first product
• Ownership over core infrastructure and security architecture
• Fast hiring process and quick start
• Supportive engineering culture focused on quality, ownership, and reliability

What happens after you apply

• Quick CV review
• Short recruiter call
• Technical interview with LITSLINK team 
• Fast decision & offer

About the Role

We are looking for a Senior Application Security Engineer (Cryptography) to join a Client’s team building a Zero-Knowledge, privacy-first product.

This role is for an internal adversary and cryptography architect — someone who validates that our Zero-Knowledge and security claims are mathematically sound, not just marketing statements.

Your mission is to actively attack our own system, identify cryptographic flaws, detect metadata leaks, and prevent key compromise before real attackers do.

Location: Remote
Cooperation Type: Full-time, long-term
Experience Level: Senior
Start: ASAP

Responsibilities

• Audit and validate cryptographic protocols (Signal Protocol, MLS, Zero-Knowledge Proofs / ZK-SNARKs)
• Review and assess security-critical implementations in mobile and backend systems
• Conduct threat modeling for Zero Trust and Zero-Knowledge architectures
• Identify vulnerabilities in mobile applications and cryptographic flows
• Perform security code reviews in Swift, Kotlin, and Java
• Execute penetration testing and security assessments using Burp Suite, Frida, Wireshark, Ghidra
• Perform mobile application security analysis (SAST / DAST)
• Design and review Private Set Intersection (PSI) schemes for secure contact discovery
• Audit secure local storage and offline-first encryption strategies (SQLCipher, Encrypted SQLite)
• Validate hardware-backed security usage (Secure Enclave / Android Keystore)
• Detect and mitigate metadata leaks, privacy risks, and key compromise threats
• Work closely with engineering teams to fix vulnerabilities and improve system security
• Document findings, security recommendations, and cryptographic risks

Requirements

• 6+ years of experience in application security, cryptography, or security engineering
• Deep understanding of cryptographic protocols (Signal Protocol, MLS, Zero-Knowledge Proofs / ZK-SNARKs)
• Strong knowledge of applied cryptography and encryption principles
• Experience reviewing and auditing security-critical code in Swift, Kotlin, or Java
• Experience with mobile application security and client-side threat models
• Hands-on experience with penetration testing tools (Burp Suite, Frida, Wireshark, Ghidra)
• Experience conducting SAST / DAST and mobile security assessments
• Experience designing or reviewing Private Set Intersection (PSI) solutions
• Experience with threat modeling for Zero Trust architectures
• Strong understanding of secure local storage and offline-first encryption (SQLCipher, encrypted SQLite)
• Familiarity with hardware-backed security (Secure Enclave, Android Keystore)
• Ability to think like an attacker and proactively break systems before others do
• English: Upper-Intermediate or higher

Nice to Have

• Experience working on Zero-Knowledge systems in production
• Experience with formal cryptographic verification or research
• Experience with reverse engineering mobile applications
• Background in security research, bug bounty, or CTFs
• Experience with privacy-preserving systems or anonymous networks
• Contributions to open-source security or cryptography projects

What We Offer

• Competitive compensation according to your experience (gross system)
• Fully remote work and long-term cooperation
• Opportunity to work on a deeply technical, cryptography-heavy security role
• Direct impact on core Zero-Knowledge and privacy architecture
• Fast hiring process and quick decision
• Supportive engineering culture focused on security, correctness, and ownership

What happens after you apply

• Quick CV review
• Short recruiter call
• Technical interview with LITSLINK team
• Technical deep-dive with the Client
• Fast decision & offer

About the Role

We are looking for a Senior Secure Mobile Engineer to join a Client’s team building a Zero-Knowledge, privacy-first mobile product.

In this role, the mobile client is the primary security boundary — responsible for encryption, key management, secure storage, and protecting sensitive data on-device.
You will work deeply with iOS and Android internals, applied cryptography, and mobile security.

Location: Remote
Cooperation Type: Full-time, long-term
Experience Level: Senior
Start: ASAP

Responsibilities

• Design, develop, and maintain a security-critical mobile client (iOS & Android)
• Implement client-side cryptography, key generation, and secure session handling
• Work with Swift (iOS) and Kotlin / Java (Android)
• Implement secure local storage using iOS Keychain, Android Keystore, and SQLCipher / encrypted SQLite
• Apply memory hygiene practices to prevent leakage of sensitive data (keys, plaintext)
• Implement certificate pinning and protect against Man-in-the-Middle attacks
• Build privacy-first, offline-capable features aligned with Zero-Knowledge principles
• Implement or integrate secure messaging protocols (Signal Protocol, MLS)
• Work with mobile threat models and platform-level security
• Collaborate with backend, cryptography, and DevSecOps teams to ensure end-to-end security
• Participate in security reviews, threat modeling, and architecture discussions
• Write clean, maintainable, and well-documented production code

Requirements

• 5+ years of mobile development experience (iOS / Android)
• Strong hands-on experience with Swift (iOS)
• Strong hands-on experience with Kotlin or Java (Android)
• Experience with mobile security and secure data handling
• Solid understanding of applied cryptography and encryption principles
• Experience with iOS Keychain and Android Keystore
• Experience implementing secure local storage (SQLCipher / encrypted SQLite)
• Experience with certificate pinning and mobile network security
• Experience working on security-critical or privacy-sensitive mobile apps
• Understanding of offline-first architectures on mobile
• Ability to take ownership of high-risk security features
• English: Upper-Intermediate or higher

Nice to Have

• Experience implementing Signal Protocol (X3DH, Double Ratchet) or MLS
• Experience with Zero-Knowledge systems
• Experience with Tor / Orbot or anonymous networking
• Experience with mobile penetration testing or reverse engineering
• Experience with Flutter / Dart (optional)
• Experience with on-device AI (TensorFlow Lite, MediaPipe, offline inference)
• Experience with advanced mobile OS security or anti-tampering techniques

What We Offer

• Competitive compensation according to your experience (gross system)
• Fully remote work and long-term cooperation
• Opportunity to work on a high-security, privacy-first product
• Direct impact on core mobile security architecture
• Fast hiring process and quick decision
• Supportive engineering culture focused on security, ownership, and quality

What happens after you apply

• Quick CV review
• Short recruiter call
• Technical interview with LITSLINK team 
• Fast decision & offer