Replay production backend failures safely.
Capture failed API requests, replay them in a safe environment, compare original vs replay results, and generate developer-ready bug reports.
ReplayStack helps backend teams reproduce issues faster by turning real production events into replayable debugging sessions.
Not a replacement for Datadog or OpenTelemetry—ReplayStack complements observability by adding replay-based debugging on top of the signals you already trust.
How we fit with your observability stack
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CloudWatch, Azure Monitor, and log analytics excel at volume & search. They rarely give you a replay button for the exact API call or job that broke.
- Request validated3ms
- Queue publish28ms
- SMTP send…
{
"to": "customer@acme.com",
"template": "receipt_v2",
"provider": "smtp_internal"
}Generic log platforms show noise. ReplayStack keeps one structured timeline per event so you can replay the exact failure—not grep your way through midnight.
Minutes to first replay
Wire the SDK or POST once—your next failed webhook shows up as a timeline, not a wall of text.
Privacy that travels with the event
Mask tokens, PANs, and custom fields before they become a screenshot in Slack.
Alerts with receipts
Every notification deep-links to the same structured story your engineers already trust.
Your stack, not ours
Node, Python, Nest, Express, Next.js—integrate over HTTP when you want full control.
Use Datadog or OpenTelemetry to find where it broke. Use ReplayStack to reproduce and debug the exact failed event.
We are not an APM or a full observability platform—we are a backend event replay and reproduction layer for capturing failed requests, replaying them safely, comparing outcomes, and turning them into actionable bug reports. Use Datadog, OpenTelemetry, or your existing stack for signals and traces; use ReplayStack when you need the real failure as a replayable session—not a replacement for those tools.
What ReplayStack does best
Five capabilities built for production bug reproduction—not generic dashboards.
Capture real failed events
Automatically capture request payloads, responses, stack traces, breadcrumbs, service version, and commit hash.
Replay safely
Replay failed events in staging or safe mode without triggering payments, emails, SMS, or destructive actions.
Compare results
See exactly what changed between the original failure and the replay attempt.
Generate bug reports
Create reproduction-ready bug reports with payload, stack trace, line number, replay result, and diff.
Works with your stack
SDKs for Node.js, Next.js, NestJS, Python, FastAPI, Flask, Django—or send events directly through the HTTP API.
| Capability | CloudWatch / Azure Monitor logs | Datadog, ELK, Grafana Loki… | ReplayStack |
|---|---|---|---|
| What it optimizes for | Durable storage, search, and infra-scale ingestion | Dashboards, metrics, traces, log analytics (with agent work) | Fast understanding & safe reproduction of one backend event |
| When a webhook or job fails | You grep, correlate IDs, and rebuild requests manually | You pivot across tools; replay is usually custom glue code | You open the timeline, inspect payload & steps, replay immediately |
| Change a field and retry | Write a script or Postman collection; hope it matches prod | Often notebooks, curl, or internal tooling—outside the log UI | Edit JSON in-place, replay, compare responses side by side |
| Story of what happened | Log lines + your mental model | Traces (great) when instrumentation spans every hop | Ordered steps per captured event—built for human debugging |
| Best companion for | Fleet health, compliance archives, infra signals | Full-stack observability budgets & on-call runbooks | Application failures where repro is the bottleneck |
Cloud logs and OpenTelemetry/Datadog traces show you the blast radius. ReplayStack is the companion layer for safe reproduction when you need the real payload, headers, and sequence—not another observability platform.
From firefight to fix—in one continuous flow
No context switching between six tabs. ReplayStack keeps capture, inspection, and replay in a single narrative.
SDK or HTTP ingest records the requests, jobs, and hooks you care about.
Failures surface as a single timeline—not a wall of stack traces.
Tweak payloads, resend, and diff outcomes without bespoke scripts.
Share the exact replay with your team and close the loop with confidence.
Teams where reproduction is the bottleneck
Especially when a bug depends on production-only context—payload shape, auth headers, external provider behavior, or the exact code version on the box.
- Backend developers
- QA engineers
- SaaS and API-heavy teams
- Agencies maintaining multiple client backends
- Teams chasing difficult-to-reproduce bugs
- Payment, order, booking, and healthcare workflows
Especially valuable when the failure hinges on
- Exact payload or user state
- Headers and downstream responses
- Environment and deployment version
- Timing-sensitive or flaky integrations
Everything that turns a failure into a fix
Three layers—capture, replay, and govern—so your team spends less time reconstructing prod and more time shipping with proof.
01 · Capture & context
Bring production into focus
Ingest the traffic that matters—webhooks, internal APIs, workers—and keep every event attached to the customer or job that triggered it.
SDK & HTTP ingestion
Instrument services with a thin SDK or POST structured events directly. Tag environment, version, and service so filters stay honest.
- Works alongside your existing log pipeline
- Designed for high-cardinality paths you actually debug
Step-by-step timelines
Each event renders as an ordered narrative: validation, IO, downstream calls, and timings—so “where it broke” is obvious on the first screen.
- Less grep, fewer missing correlation IDs
- Shareable view for support and engineering
Live health signal
Watch volume, error rates, and slow steps as events arrive. Spot regressions before they become all-hands incidents.
- Fits on-call workflows without extra dashboards
- Pairs with alerts when thresholds slip
02 · Replay & verify
Prove the fix before you merge
ReplayStack is built for the moment after you’ve found the stack trace—when you still need to know if the patch actually fixes the real payload.
Replay & response diff
Re-run the exact event—or a variation—against staging or production-safe endpoints. Compare status codes, bodies, and timings side by side.
- Stop maintaining one-off curl scripts
- Keep a paper trail of what you tried
Payload workspace
Edit JSON with guardrails: tweak headers, swap providers, or simulate edge cases before you send the next replay.
- Validate shape before the request leaves ReplayStack
- Great for flaky third-party integrations
Shareable timelines
Every event has a stable narrative—deep-link it in Linear, Jira, or Slack so support and engineering debate the same facts, not screenshots.
- Fewer “can you send the curl?” loops
- Onboarding with real production shapes, safely masked
03 · Trust & operations
Safe by default, loud when it counts
Security and alerting stay tightly coupled to the event model, so compliance reviewers see controls—not ad-hoc scripts.
Masking & policy
Redact tokens, secrets, PANs, and custom fields automatically. Export only what policy allows when you share outside the core team.
- Rules travel with the workspace, not a wiki page
- Fewer accidental leaks in tickets or Slack
Routing & alerts
Notify the right channel when specific services, routes, or customers fail—email, Telegram, or downstream webhooks.
- Noise-aware thresholds per project
- Escalate with the timeline link attached
Outbound webhooks
Fan failures out to the tools you already run—HTTP callbacks alongside email, Telegram, or Slack-style routing when an alert fires.
- Wire alerts into tickets or chat without a custom poller
- HTTP APIs mirror what you configure in the UI
Want implementation detail? Browse the docs for SDK snippets, HTTP examples, and framework guides.
Questions before you dive in?
Security reviews, enterprise plans, or integrations—we read every message and respond as fast as we can.
Contact usPricing that rewards fixing—not hoarding logs
Start free while you wire up your first project. Scale when replay volume grows, with retention and alerts that match how your team actually works.
Built by developers, for developers
We've spent countless hours debugging production issues at 3 AM. ReplayStack was born from our frustration with existing tools that were either too complex, too expensive, or simply didn't solve the real problem.
Our mission is simple: make backend debugging as easy as frontend debugging. No more digging through logs, no more manual curl requests, no more guessing.
Ready to turn every failure into a replayable story?
Join teams who treat ReplayStack as the proof layer next to their cloud logs—same incidents, dramatically less guesswork.
No credit card · Free tier forever · Upgrade when replay volume grows