Postman startup times have ballooned to 14+ seconds. The app becomes sluggish after running for a while, requiring restarts. Developers report the native application is extremely slow or unresponsive, especially after updates. One user measured 399MB disk space usage for what should be a simple HTTP client.

Postman consumes excessive system resources. CPU fans constantly spinning, CPU usage spiking to 50-60% while barely doing anything. Memory consumption grows over time, especially with large workspaces or long-running sessions. Multiple GitHub issues report this problem persisting across versions.

Postman doesn't work well with large collections or on lower-end machines. The app freezes randomly or crashes completely. Users with hundreds of API endpoints experience significant lag when navigating or searching collections.

Postman v10 removed offline mode entirely. Users MUST create an account and login to use the app. You cannot save requests to collections without signing in. This is especially problematic for developers in corporate environments where external account creation is restricted.

What started as a simple REST client has become bloated with API documentation, mock servers, monitoring, and collaboration features. Developers who just want to test APIs must navigate through unnecessary complexity. The constant push toward web app and new features makes it feel overwhelming.

Many features depend on an active internet connection. The lack of fully functional offline mode is restrictive in low-connectivity environments or air-gapped development setups. Enterprise developers in secure environments can't use Postman at all.

Pre-request and test scripts have a steep learning curve. Error messages are unclear, making debugging difficult. New users struggle with advanced features like environments, dynamic variables, and test assertions. Documentation exists but practical application is challenging.

Logging in means API requests and data are synced to Postman's cloud servers. This raises significant privacy concerns for developers handling sensitive data, client APIs, or proprietary information. Many companies prohibit cloud sync for security reasons.

Users report losing all their collections, variables, and environments after refusing to create an account or after updates. Data cannot be recovered even after later creating an account. Critical workflow data lost permanently.

Team collaboration features have sync issues causing data conflicts, duplicate collections, and lost changes. Managing team permissions, collection versioning, and API definition updates becomes complicated with larger teams. Changes sometimes don't sync properly between team members.

Postman's March 2026 pricing update limits the free plan to just 1 user. Previous free teams must upgrade or lose collaboration features. The constant addition of paid add-ons makes pricing confusing, with costs escalating quickly for teams.

Postman doesn't support direct connections to databases like MongoDB, PostgreSQL, or CosmosDB. Users must export data manually for testing, adding extra steps to workflows. Competitors offer better database integration capabilities.

Trustpilot reviews cite poor customer service on billing issues. Postman is inflexible about refunding mistakenly added seats. Cancellation requests through the website don't complete and must be manually processed, with some requests remaining unprocessed for weeks.