GitLab Duo - Replit alternative

GitLab Duo is an AI assistant suite integrated into the GitLab DevSecOps platform. It provides AI-native features across IDE extensions and the GitLab UI. The core offering costs $19 per user per month as an add-on. Solo developers working within GitLab's ecosystem gain AI assistance without leaving their version control environment. The Replit alternative approach keeps code suggestions, chat, and repository management in one unified platform.

Strengths

• Features span the complete software development lifecycle, including code generation, test creation, vulnerability analysis, and merge request summaries.
• Supports VS Code, JetBrains IDEs, Visual Studio, Eclipse, Neovim, and GitLab Web IDE with language server protocol implementations for consistent cross-platform behavior.
• Works with 20+ languages including C++, Go, Java, JavaScript, Python, Rust, TypeScript, and infrastructure-as-code formats like Terraform and Kubernetes Resource Model.
• GitLab 18.0+ includes Duo Core automatically with Premium/Ultimate subscriptions, providing 2,000 code suggestions and 100 chat requests per user monthly at no extra cost.
• Self-hosted deployment option isolates AI gateway and models in your private network, eliminating external API dependencies for enterprises requiring air-gapped environments.
• Deep integration with GitLab CI/CD pipelines, issue tracking, and merge request workflows enables context-aware assistance throughout development tasks.

Weaknesses

• Pro and Enterprise tiers require purchasing and assigning seats to individual team members, adding administrative overhead compared to automatic provisioning models.
• Core tier limits (2,000 suggestions, 100 chat requests monthly) may constrain heavy users before upgrading to paid Pro seats.
• Requires existing GitLab Premium or Ultimate subscription before adding Duo capabilities, creating a higher baseline cost than standalone AI coding tools.
• Language support varies significantly across IDEs; some combinations require manual configuration or third-party extensions.
• Tightly coupled to GitLab ecosystem; developers using GitHub, Bitbucket, or other platforms cannot leverage most features without migration.

Best for

Teams already standardized on GitLab who want AI coding assistance integrated directly into their existing DevSecOps workflows without adopting separate tools.

Pricing plans

• GitLab Duo Core — Included with Premium/Ultimate — 2,000 code suggestions + 100 chat requests per user/month
• GitLab Duo Pro — $19/user/month — Unlimited usage, code generation, test generation, refactoring, chat (requires Premium or Ultimate subscription)
• GitLab Duo Enterprise — $39/user/month — Everything in Pro plus summarization tools, expanded chat context, root cause analysis, code review, vulnerability features (requires Ultimate subscription)
• GitLab Duo with Amazon Q — Contact sales — Amazon Q Developer Pro integration for self-managed instances

Tech details

• Type: AI-powered DevSecOps platform add-on
• IDEs: VS Code, JetBrains (IntelliJ, PyCharm, etc.), Visual Studio 2022, Eclipse, Neovim, GitLab Web IDE
• Key features: Code completion/generation, test generation, code refactoring, vulnerability explanation/resolution, chat assistance, merge request summaries, root cause analysis, documentation generation
• Privacy / hosting: Self-hosted option available with Duo Enterprise for air-gapped deployments. SaaS version processes requests through GitLab infrastructure. Data retention follows GitLab's standard policies.
• Models / context window: Uses generative AI models; code completion typically returns results under one second, larger generations may take 5+ seconds. Specific model names and context windows not publicly documented.

When to choose this over Replit

• Your team already uses GitLab for version control and CI/CD; adding Duo eliminates context-switching to external coding assistants.
• You require fully self-hosted AI infrastructure with no external API dependencies for regulatory compliance or security policies.
• You need AI assistance integrated across the DevSecOps lifecycle (planning, security scanning, deployment) rather than just coding environments.

When Lovable may be a better fit

• You want a standalone coding environment without requiring an existing GitLab subscription as the foundation.
• Your team uses GitHub, Bitbucket, or other version control platforms and doesn't plan to migrate infrastructure.
• You prefer simpler per-seat pricing without navigating GitLab's tiered subscription model (Free/Premium/Ultimate) plus add-on combinations.

Conclusion

GitLab Duo transforms the GitLab platform into an AI-augmented development environment. The automatic inclusion of Core features in GitLab 18.0+ Premium/Ultimate subscriptions lowers the barrier for existing customers to experiment with AI assistance. Organizations prioritizing unified DevSecOps tooling gain significant workflow efficiency by keeping AI features inside their existing GitLab instance rather than adopting separate solutions.

Sources

• Official site: https://about.gitlab.com/gitlab-duo/
• Docs: https://docs.gitlab.com/user/gitlab_duo/
• Pricing: https://about.gitlab.com/pricing/

FAQ

What GitLab subscription do I need for Duo features?
GitLab Duo requires a Premium or Ultimate subscription. GitLab 18.0+ automatically includes Duo Core. Pro and Enterprise require purchasing additional seats.

Can I use GitLab Duo without GitLab's version control?
No. Duo integrates tightly with GitLab repositories, CI/CD pipelines, and merge requests. Teams using other platforms cannot access most functionality.

Which programming languages does Code Suggestions support?
Default support includes C, C++, C#, Go, Java, JavaScript, Python, Ruby, Rust, TypeScript, PHP, Swift, and infrastructure-as-code formats. Support varies by IDE; additional languages can be manually configured.

How does self-hosted Duo differ from the SaaS version?
Self-hosted deployments keep the AI gateway and language models entirely within your private network, eliminating external API calls. This requires Duo Enterprise and GitLab Self-Managed instances.

What happens if I exceed Core tier limits?
Core tier provides 2,000 code suggestions and 100 chat requests per user monthly. After hitting limits, you must upgrade to Pro or Enterprise for unlimited access.

Does GitLab Duo work in all JetBrains IDEs?
The Duo plugin supports JetBrains IDEs, but some languages require additional plugins. Check JetBrains documentation for your specific IDE's language support.