We fix, upgrade, and scale Rails apps.

Senior Rails engineers. Practical work. No theater. Boston and Pune.

We also help companies add practical AI to real products: private AI workflows, Rails AI features, LLM-backed internal tools, AI review loops, and CTO mentoring for teams moving from experiments to production.

Book a consulting call
See Ruby on Rails services
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Explore Miru

• Ruby on Rails application development and deployment.
• Rails upgrades from older versions to modern Rails.
• Rails maintenance for long-running SaaS products.
• Rails performance tuning, database optimization, caching, and scalability.
• Rails security reviews: authentication, authorization, multi-tenant access, API boundaries, CI checks, and production hardening.
• React, React Native, Next.js, and full-stack product engineering.
• DevOps, deployment, monitoring, and production support.
• AI for Rails teams: private AI setup, RAG, local LLM workflows, internal LLM wiki, agentic development workflows, and AI-assisted code review.
• CTO AI transformation: training, mentoring, rollout plans, quality gates, and team operating practices.

• 10+ years building and maintaining Ruby on Rails applications.
• Rails Foundation Contributing Member.
• Rails contributors on the team, including members of the Rails Issues team.
• 50+ delivered projects across startups and larger teams.
• Offices in Boston, MA and Pune, India for global collaboration.
• Deep Rails, React, Postgres, performance, and product delivery experience.
• Public writing culture: we document Rails, Ruby, React, AI, performance, and production lessons on the Saeloun blog.

We review architecture, simplify controllers and models, improve data boundaries, build features, and help teams make Rails apps easier to maintain.

Good fit when:

• the app is growing faster than the codebase can handle
• CI is slow or unreliable
• production bugs keep returning
• product delivery is blocked by old design choices
• the team needs senior Rails review without hiring a full-time principal engineer

Rails consulting services

We plan and ship Rails upgrades as small, reviewable changes.

That means:

• audit dependencies
• stabilize tests
• remove deprecations
• update CI
• write a rollout plan
• verify after deploy: smoke checks, performance checks, and rollback path

Good fit when:

• Rails is several versions behind
• upgrades keep getting postponed
• dependency updates are risky
• tests are noisy
• the team wants a predictable upgrade path

Talk to us about a Rails upgrade

We review how data moves through the app: authentication, authorization, tenant scoping, background jobs, exports, APIs, admin paths, file uploads, secrets, and deployment settings.

Good fit when:

• the app handles sensitive customer data
• Model.find(params[:id]) appears in tenant-sensitive code
• admin features bypass normal policy checks
• background jobs perform work without an explicit actor
• API authorization is weaker than HTML controller authorization

Rails security consulting

We measure first. Then we fix the expensive path: SQL, object allocations, caching, job queues, N+1 queries, Postgres indexes, memory growth, deploy shape, or frontend bottlenecks.

Good fit when:

• p95 latency is drifting up
• database load is high
• Sidekiq or Solid Queue jobs are stuck
• memory usage keeps climbing
• the team needs a clear performance plan instead of random tuning

Performance optimization services

We add AI where it measurably improves product or engineering decisions.

Examples:

• private AI assistants for engineering teams
• local LLM-backed knowledge systems
• internal LLM wiki for codebase, product, support, and operations knowledge
• RAG over private docs and application data
• AI features inside Rails products
• evals and quality gates for AI output
• GitHub Actions, CodeRabbit, Copilot, CI, lint, and test workflows that adapt to team preferences
• CTO training for AI transformation and private AI setup

Guardrails first:

• private data stays private
• evals before rollout
• quality gates stay mandatory
• no bypassing review or tests
• prefer small, auditable stacks over heavy vendor lock-in

AI should improve the team's default judgment. It should not replace it.

Book an AI setup call

• Miru: time tracking, invoicing, and employee benefits, built with Ruby on Rails and React.
• Saeloun Blog: our public Rails, Ruby, React, AI, and product engineering writing.
• Plate: Rails templates and starter patterns.
• Uploadcare Rails: Rails integration work around Uploadcare.

Saeloun contributes to Ruby, Rails, React, open source, meetups, conferences, and writing. We help run community events, publish regular Rails updates, and support the Rails ecosystem through contributions and sponsorship.

Saeloun joined the Rails Foundation as a Contributing Member.

The fastest way to start:

• tell us your Rails version
• describe the production pain
• share whether the priority is upgrade, performance, security, AI, product delivery, or maintenance
• include relevant logs, traces, screenshots, PRs, or architecture notes

Contact Saeloun

• Website: saeloun.com
• Blog: blog.saeloun.com
• Rails consulting: Ruby on Rails services
• Contact: Let's talk
• X: @HiSaeloun