Choose a Bazel build platform around three decisions: who operates your cache and execution service, where it runs, and how your engineers investigate and fix problems. Hermetiq, BuildBuddy, EngFlow, Aspect, and self-managed Buildbarn address those decisions differently.
A team adopting remote execution has different needs from a team that already operates Buildbarn and wants better intelligence. This guide is written by Hermetiq; the recommendations are our assessment, and product claims link to official documentation.
Start with the responsibility you want to hand over
Remote caching reuses previously built outputs. Remote execution runs actions on other machines. A CI runner hosts the Bazel process that coordinates those actions. Buying one does not automatically replace the others.
How the five options differ
Hermetiq: managed builds or intelligence for existing Buildbarn
Hermetiq sells managed remote cache and execution with build intelligence and AI. Teams that already operate Buildbarn can buy the intelligence separately. There are four offerings:
- Cloud Managed Builds: Hermetiq hosts the remote cache, execution service, and intelligence.
- On-Prem Managed Builds: Cache, execution, and intelligence run in your environment, with Hermetiq provisioning and support. Operating responsibilities are agreed for the deployment.
- Cloud Intelligence: You keep and operate your existing Buildbarn; Hermetiq hosts the intelligence.
- On-Prem Intelligence: You run your existing Buildbarn and Hermetiq’s intelligence in your environment.
The advantage is a choice of infrastructure ownership without giving up Buildbarn-aware investigation. Connected data sources can combine Bazel events with action timing, cache events, profiles, and infrastructure telemetry. The same AI capabilities apply across the four offerings, subject to connected telemetry and access.
The tradeoff is integration work where deeper telemetry is not yet connected. BEP alone does not provide every queue, worker, storage, or cache-event signal. An existing Buildbarn deployment needs the relevant integrations and permissions; buying intelligence does not transfer operation of that deployment to Hermetiq.
In our recorded build walkthrough, Hermetiq supplies failed-action evidence, Codex fixes an undeclared input, and Bazel verifies the target before an unchanged rerun hits the remote cache. This demonstrates a client-assisted workflow. The coding client needs repository and terminal access to apply changes and rerun work; it is not evidence of unattended operation across every failure class.
BuildBuddy: an integrated Bazel developer workflow
BuildBuddy combines a results UI, remote cache, and remote execution. Its RBE service supports hosted and on-prem deployments, custom container images, automatic executor scaling, and action deduplication. Remote Bazel adds a way to run the Bazel command itself remotely.
That breadth is useful when the goal is a coherent developer experience across results and execution. The deployment tradeoff is the enterprise configuration you take on when self-hosting: BuildBuddy’s setup guide covers its application and executor deployment. Confirm the required worker platforms, storage, identity, and integration features in your chosen deployment.
BuildBuddy also documents MCP access to build metadata, logs, artifacts, and target statuses in Cloud and on-prem. Its examples include local coding agents investigating failed tests, fixing code, and diagnosing performance. AI connectivity is an existing part of this comparison.
EngFlow: supported execution across build clients
EngFlow supports REAPI-compatible clients including Bazel, Reclient, and Soong. It offers cloud and on-prem deployments, managed or self-managed operation, autoscaling, and monitoring integrations. This makes it a candidate when multiple build systems or enterprise execution requirements drive the purchase.
The tradeoff depends on the operating model you choose. A managed service delegates cluster work; a self-managed cluster leaves an internal operating role. Compare the support boundary, execution environment, and monitoring access against your incident process.
EngFlow’s AI Agent Access documentation describes a beta MCP interface for build failures, flaky targets, performance, individual actions, and artifacts. It explicitly includes local code fixes by a connected agent. Availability depends on enabled cluster features, so test the workflow on the cluster you would actually use.
Aspect: CI runners and the surrounding Bazel workflow
Aspect Workflows combines persistent CI runners, remote cache, remote execution, and a Build & Test UI. It works with existing CI systems and ordinary Bazel commands; the Aspect CLI is optional. Deployments can run in your cloud account or in an isolated Aspect-hosted environment.
Aspect’s advantage is scope when cold CI runners and the surrounding workflow are substantial parts of the problem. The tradeoff is that evaluating the whole runner and workflow platform involves more than comparing a remote-execution endpoint. Measure the runner contribution separately from cache and remote-action performance.
Aspect documents an MCP server for searching its documentation, which helps coding assistants use current setup and workflow guidance. That documented interface should not be treated as proof of live invocation or infrastructure telemetry access. Ask for the exact investigation and repair workflow you need rather than inferring it from an MCP label.
Self-managed Buildbarn: direct implementation control
Buildbarn’s example deployments combine storage, scheduling, workers, and other components for remote caching and execution. The open-source implementation gives your platform team direct control over configuration and changes. Buildbarn Portal also provides build-event capture; an open-source stack does not imply an absence of a UI.
The tradeoff is the engineering work: deployment, capacity, upgrades, monitoring, authentication, and incident response remain your responsibility unless you contract for help. Components and source access provide control; they do not make operations effortless. Add Hermetiq Cloud Intelligence or On-Prem Intelligence when you want correlated investigation and AI while retaining that operating model.
Evaluate the AI with an actual build problem
More data is useful when it changes the diagnosis or makes the fix verifiable. An MCP endpoint, a long tool list, or a large event count is not enough to rank agents. Compare the same task, available permissions, and relevant data for each platform:
- Start with a real failure or regression. Use a reproducible missing input, recurring test failure, cache regression, or queue delay from your own repository.
- Inspect the evidence. Can the agent identify the affected action and distinguish source, toolchain, configuration, and infrastructure causes? Does it expose missing data rather than guess?
- Review the change. Determine what the service does, what the coding client does, and which permissions allow either to edit files or infrastructure.
- Verify the outcome. Rerun affected work, compare equivalent inputs and conditions, and retain the patch and resulting build evidence.
For performance evaluation, measure cold and warm runs separately, keep the target set and toolchain consistent, and record queue, transfer, execution, and client time. A successful demonstration on one small repository establishes a workflow; your own workload establishes its value.
Choose the fit, then prove it
Shortlist Hermetiq when you want managed builds with AI or intelligence for the Buildbarn you already run. Include BuildBuddy when an integrated Bazel developer platform is the priority, EngFlow when execution requirements span clients and deployment models, and Aspect when CI runners and workflow integration are central. Choose self-managed Buildbarn when direct implementation control justifies the ongoing operating work.
Cloud versus on-prem is one decision. Managed builds versus intelligence for existing infrastructure is another. Make both explicit before comparing agent behavior or deciding who will respond when builds stop.
Choose how Hermetiq fits your builds.
Get managed remote cache and execution with AI, or add intelligence to your existing Buildbarn. Choose Cloud or On-Prem for either path.