Keploy

Keploy intercepts live HTTP/HTTPS traffic at the network layer using eBPF (extended Berkeley Packet Filter) on Linux or syscall hooking on other platforms, capturing request/response pairs with full headers, bodies, and timing metadata without requiring code instrumentation. This approach enables zero-modification traffic capture directly from running applications, recording both inbound client requests and outbound service calls in real-time.

Keploy analyzes captured HTTP traffic and automatically generates executable test cases by extracting request parameters, response assertions, and dependency chains. It uses pattern matching and heuristics to identify test boundaries (request start/end), deduplicate similar requests, and create parameterized test templates that can be executed against different versions of the application.

Keploy extracts outbound API calls from captured traffic and automatically generates mock stubs (recorded responses) that can be replayed during test execution. These stubs are stored as YAML or JSON files and injected into the application via a local mock server, allowing tests to run in isolation without hitting real external services. The system maintains request-response mappings with fuzzy matching to handle minor variations in requests.

Keploy executes generated test cases by replaying recorded requests against the application and comparing actual responses against captured baseline responses. It uses byte-level or semantic comparison (depending on content type) to validate that responses match, with configurable assertion strategies for handling non-deterministic fields like timestamps or request IDs. Test results are reported with detailed diffs showing where responses diverged.

Keploy generates executable test code in multiple programming languages (Go, Java, Python, Node.js) from captured traffic, using language-specific idioms and testing frameworks (Go's testing package, JUnit, pytest, Jest). The code generator maintains a template system for each language, inserting captured request/response data into framework-appropriate structures, and produces code that can be immediately run without additional configuration.

Keploy captures database queries and state changes that occur during traffic recording, then replays those state changes during test execution to ensure the application operates with the same data context. It intercepts database calls (SQL, NoSQL) and records the queries and results, allowing tests to run against a consistent, reproducible data state without requiring manual database setup or teardown scripts.

Keploy maintains version control for captured traffic, test cases, and stubs, allowing teams to track changes over time and synchronize test definitions across environments. When traffic is re-recorded, Keploy diffs new traffic against previous recordings and updates test cases incrementally, preserving manual edits while incorporating new observations. This enables collaborative test maintenance where multiple team members can contribute to test suites without conflicts.

Keploy integrates with CI/CD systems (GitHub Actions, GitLab CI, Jenkins, CircleCI) via CLI commands and webhooks, executing test suites automatically on code changes and reporting results back to the pipeline. It generates structured test reports (JSON, HTML, JUnit XML) that integrate with standard CI/CD dashboards, and can block deployments if tests fail or coverage thresholds aren't met.