Best API Testing Tools for Claude Code

Engineering teams shipping with AI have a new bottleneck: validation. Code output has accelerated. Quality hasn't. Checksum closes the gap. Checksum is a continuous quality platform with a suite of AI agents that handle testing end-to-end, at every stage of the development lifecycle. Where most tools wait for a human to trigger them, Checksum runs autonomously in the background, generating tests, executing them, and repairing failures without manual intervention. Seventy percent of test failures are resolved automatically through real-time auto-recovery. The platform covers every layer: end-to-end UI flows via Playwright, API endpoint chains, and targeted CI tests scoped to exactly what changed in a PR. All tests land as real code in your repository and are delivered as standard Playwright, owned by your team. Checksum is fine-tuned on 1.5+ million test runs and integrates natively with Cursor, Claude Code, and 100+ AI coding agents. Type /checksum and your coding agent's output gets tested before it ever reaches review. Generation and healing happen on Checksum's cloud infrastructure which means no LLM tokens consumed, no local resources required. The result: test suites that stay green as the product evolves, fewer regressions reaching production, and release confidence that scales alongside AI output.

Akto is an open source, instant API security platform that takes only 60 secs to get started. Akto is used by security teams to maintain a continuous inventory of APIs, test APIs for vulnerabilities and find runtime issues. Akto offers tests for all OWASP top 10 and HackerOne Top 10 categories including BOLA, authentication, SSRF, XSS, security configurations, etc. Akto's powerful testing engine runs variety of business logic tests by reading traffic data to understand API traffic pattern leading to reduced false positives. Akto can integrate with multiple traffic sources - Burpsuite, AWS, postman, GCP, gateways, etc.