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Tusk Drift

Open-source tool for automating API tests

Details

External ID
45887536
Source
HN
Company
—
Product
Tusk Drift
Website domain
github.com
Launched
Nov. 11, 2025
Cohort
—
Upvotes
56
Upvotes percentile
0.8438864628820961
Tags
—
Fetched at
Sept. 7, 2026, 9:25 p.m.
Updated at
Sept. 7, 2026, 9:25 p.m.

Description

Hey HN, I'm Marcel from Tusk. We’re launching Tusk Drift, an open source tool that generates a full API test suite by recording and replaying live traffic.How it works:1. Records traces from live traffic (what gets captured)2. Replays traces as API tests with mocked responses (how replay works)3. Detects deviations between actual vs. expected output (what you get)Unlike traditional mocking libraries, which require you to manually emulate how dependencies behave, Tusk Drift automatically records what these dependencies respond with based on actual user behavior and maintains recordings over time. The reason we built this is because of painful past experiences with brittle API test suites and regressions that would only be caught in prod.Our SDK instruments your Node service, similar to OpenTelemetry. It captures all inbound requests and outbound calls like database queries, HTTP requests, and auth token generation. When Drift is triggered, it replays the inbound API call while intercepting outbound requests and serving them from recorded data. Drift’s tests are therefore idempotent, side-effect free, and fast (typically <100 ms per test). Think of it as a unit test but for your API.Our Cloud platform does the following automatically:- Updates the test suite of recorded traces to maintain freshness- Matches relevant Drift tests to your PR’s changes when running tests in CI- Surfaces unintended deviations, does root cause analysis, and suggests code fixesWe’re excited to see this use case finally unlocked. The release of Claude Sonnet 4.5 and similar coding models have made it possible to go from failing test to root cause reliably. Also, the ability to do accurate test matching and deviation classification means running a tool like this in CI no longer contributes to poor DevEx (imagine the time otherwise spent reviewing test results).Limitations:- You can specify PII redaction rules but there is no default mode for this at the moment. I recommend first enabling Drift on dev/staging, adding transforms (https://docs.usetusk.ai/api-tests/pii-redaction/basic-concep...), and monitoring for a week before enabling on prod.- Expect a 1-2% throughput overhead. Transforms result in a 1.0% increase in tail latency when a small number of transforms are registered; its impact scales linearly with the number of transforms registered.- Currently only supports Node backends. Python SDK is coming next.- Instrumentation limited to the following packages (more to come): https://github.com/Use-Tusk/drift-node-sdk?tab=readme-ov-fil...Let me know if you have questions or feedback.Demo repo: https://github.com/Use-Tusk/drift-node-demo

Enrichment

Theme
proxy, dns, and networking tools
Vertical
Horizontal
Function
Workflow automation
Audience
Developer
AI stance
Not AI
Project type
Hobby / open-source project
Normalized one-liner
api test automation tool
Manually corrected
False

Could you build this?

Partial The UI and basic API recording/playback scripts are straightforward, but reliably intercepting distributed network traffic, synthesizing valid mock states, and auto-generating deterministic regression test suites require non-trivial systems programming.

What it would actually take: A production implementation requires a network proxy or eBPF/OpenTelemetry-based middleware to capture ingress/egress HTTP calls and side effects (database queries, 3rd party calls). A core replay engine must sanitize non-deterministic payloads (timestamps, UUIDs, auth tokens), generate mock responses for external dependencies, and compute semantic diffs on replayed requests. The stack would typically leverage Go or Rust for low-overhead interception alongside a testing framework generation layer.

Discussion

17 comments analyzed.

Competitors mentioned: vcrpy (Python VCR library), mitmproxy (HTTP-level recording/replay), Postman Collections (HTTP request/response recording)

Concerns raised: Language-specific; requires SDK installation in backend during recording, Replayed tests become brittle as dependencies and schemas evolve, Non-deterministic data (timestamps, IDs) causes false failures, Not designed for cross-language rewrites or browser-exported requests, Manual re-recording needed locally when schemas change

Feature requests: Replay tests against different URLs (e.g., rewritten backend in different language), Create tests from browser network tab exports (language-agnostic), Automated schema change detection and trace re-recording, Custom matching rules for application-specific non-deterministic data

Competitors

Other products that read as similar to this one — 71 launches clear the similarity bar, closest 8 shown.

Attention rank: #14 of 72 (itself plus its competitors, highest first — normalized so YC and Product Hunt are compared fairly).

Launched 7 days after the earliest competitor.

Other launches for this product

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