The developer tool landscape is having a quiet revolution, and it is happening in a category most people do not think much about: API clients. Bruno is eating into Postman’s dominance, and the reason says something fundamental about where developer tool preferences are heading.
Bruno stores API collections as plain text Bru markup files in your filesystem, enabling Git-based collaboration with no cloud sync, no accounts, no subscriptions. It is offline-only, open-source, and fast. And the developer community is voting with their feet.
Let me unpack why this matters and what it signals about the broader developer tools market.
The Design Philosophy Divide
At the deepest level, this is a clash between two fundamentally different approaches to developer tooling:
Postman: Cloud-First Architecture
Postman started as a simple Chrome extension for testing APIs. Over the years, it evolved into a comprehensive API development platform with cloud sync, team workspaces, API documentation, mock servers, monitoring, and flow-based testing. That evolution required a cloud-first architecture — your collections, environments, and test scripts live in Postman’s cloud, synced across devices and team members.
The cloud-first approach made sense when it was introduced. Teams needed shared access to API collections, and Postman’s workspace model solved real collaboration problems. But it also introduced dependencies: you need an account to use the tool, your data lives on someone else’s servers, and the application has become progressively heavier as features accumulated. On large projects (100+ requests, complex test scripts, multiple environments), Postman can feel sluggish — startup times increase, sync operations block the UI, and the Electron shell consumes significant memory.
Bruno: Filesystem-First Architecture
Bruno takes the opposite approach. Collections are stored as .bru files — plain text markup that lives in your project directory alongside your code. There is no cloud component. No account creation. No sync service. The application reads from and writes to the filesystem directly.
The Bru markup format is human-readable and diff-friendly:
meta {
name: Create User
type: http
seq: 1
}
post {
url: {{baseUrl}}/api/users
body: json
auth: bearer
}
auth:bearer {
token: {{authToken}}
}
body:json {
{
"name": "Jane Doe",
"email": "[email protected]",
"role": "admin"
}
}
tests {
test("should return 201", function() {
expect(res.status).to.equal(201);
});
}
This is just a text file. You can cat it, grep through it, diff it, and version-control it with the same Git workflow you use for everything else. There is no proprietary binary format, no database, no sync layer between you and your data.
Workflow Implications: Git PRs vs. Postman Workspaces
The practical difference in team collaboration is dramatic.
With Postman: Someone on your team modifies an API collection in their Postman workspace. The change syncs to the cloud. Other team members see the update next time they open Postman or when the sync happens. There is no review process for the change. If the modification breaks existing tests or misrepresents the API contract, you find out when something downstream fails. Postman does offer version history and forking, but these are Postman-specific concepts that exist outside your normal development workflow.
With Bruno: Someone modifies a .bru file. They commit the change and open a pull request. The API collection change shows up in the PR diff alongside the code change that necessitated it. Reviewers can see exactly what changed in the API definition, comment on it, request modifications, and approve it through the same process they use for every other code change. The API collection change and the code change are atomically linked in the same commit.
This is not a minor workflow improvement — it fundamentally changes how teams manage API contracts. When the backend developer modifies an endpoint’s request format, the .bru file update is in the same PR. The frontend developer reviewing the PR sees both the code change and the API collection change. There is no “someone forgot to update the Postman collection” problem because the collection IS the codebase.
Environment management follows the same pattern. Bruno stores environment variables in .bru files that can be committed (or gitignored for secrets). Different branches can have different environment configurations. You can spin up a feature branch with a modified API endpoint URL and the Bruno collection automatically uses it. With Postman, you manage environments separately from your code, which means environment configuration drifts from the code it supports.
Performance Characteristics
Bruno is noticeably faster than Postman for daily use:
- Startup time: Bruno launches in 1-2 seconds. Postman can take 5-15 seconds on large workspaces, with additional time for sync operations.
- Memory usage: Bruno typically uses 100-200 MB of RAM. Postman regularly consumes 500 MB - 1.5 GB, especially with multiple tabs and large collections.
- Request execution: Both tools are comparable for actual HTTP request execution, but Bruno’s response rendering is faster because it is not simultaneously managing sync state, telemetry, and cloud operations.
- Search and navigation: Finding a specific request in a large Bruno collection is essentially a filesystem search (instant). In Postman, searching large workspaces can have noticeable lag.
For individual developers or small teams, the performance difference is a convenience. For teams with 200+ API requests across multiple services, the performance gap becomes a productivity issue. Nobody wants to wait 10 seconds for their API client to start up when they just want to fire a quick test request.
What This Signals About Developer Tool Preferences
Bruno’s growth is part of a broader pattern in developer tooling. Developers are increasingly gravitating toward tools that:
-
Store data as plain text files rather than proprietary formats or cloud databases. This is the same impulse behind Infrastructure-as-Code, GitOps, and configuration-as-code movements. If it can be a text file, developers want it to be a text file.
-
Integrate with existing workflows rather than creating parallel universes. Git is the collaboration layer. CI/CD is the automation layer. Developers do not want separate collaboration and automation models for every tool category.
-
Work offline and fast without cloud dependencies. After years of everything moving to the cloud, there is a counter-movement toward local-first tools that work without network connectivity. Bruno, Obsidian, and Linear (with its offline-first architecture) all reflect this trend.
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Are open-source or at least open-format. Developers have been burned by vendor lock-in at the tool level (not just the infrastructure level). Postman’s data format is proprietary — if Postman shuts down or changes pricing, migration is painful. Bruno’s
.bruformat is open, and the tool is MIT-licensed. -
Do one thing well rather than becoming platforms. Postman’s evolution into an “API Platform” with monitoring, mock servers, documentation, and flows has made it powerful but complex. Developers who just want to test APIs find themselves navigating a tool that tries to do everything.
The Trade-offs Are Real
Bruno is not a perfect Postman replacement. There are legitimate gaps:
- Mock servers: Postman’s built-in mock server is genuinely useful for frontend development against APIs that do not exist yet. Bruno does not have this.
- API monitoring: Postman can run collections on a schedule and alert you when endpoints fail. This is valuable for API health monitoring.
- API documentation: Postman’s auto-generated documentation from collections is widely used. Bruno does not generate documentation.
- Non-technical users: Product managers, QA testers, and other non-developers who use Postman for API exploration face a steeper learning curve with Bruno.
The question for each team is: do the workflow benefits of Git-native API collections outweigh the feature gaps? For many engineering teams, the answer is increasingly yes.
What has your experience been with API testing tools? Has anyone here made the Postman-to-Bruno switch? I am curious about the migration experience and what you miss (or do not miss).