Error monitoring from Germany
Fehlo collects the errors in your apps and websites with stack trace, breadcrumbs and context, so you see them before your customers call. It accepts events from the sentry SDKs and stores them on a server in Nuremberg, Germany.
Switching from Sentry: one line
Fehlo speaks the protocol of the sentry SDKs. You change the DSN and nothing else. Your SDK and code stay, and so does sentry-cli for releases, source maps, ProGuard mappings and debug symbols.
That holds for JavaScript, Python, PHP, Java and Android, iOS, Flutter, .NET, Go and Ruby. A new project takes two minutes: pick the platform, copy the code, trigger a test error.
import * as Sentry from "@sentry/node"; Sentry.init({- dsn: "https://a1b2c3@o123456.ingest.de.sentry.io/4507",+ dsn: "https://a1b2c3@app.fehlo.de/7", environment: "production",});What Fehlo does
- Issues
- Grouped, with stack trace, lines of code, local variables, the steps that led up to the error, and the spread across browsers, releases or customers.
- Fix prompt
- One click copies an issue as a prompt for Cursor, Claude Code or Lovable. Variable values stay out, so no customer data travels with it.
- Alerts
- On new issues, spikes and outages, by email, Microsoft Teams, Discord, Google Chat, ntfy, Zulip or webhook. When a resolved issue comes back, Fehlo tells you again.
- Uptime and status pages
- HTTP, ping, TCP, SSL certificates and heartbeats for cron jobs. Status pages, public or for members only.
- Performance and logs
- Slow endpoints with p50 and p95, error rate and N+1 queries. Logs with search, filters and a live view, linked to issues through traces.
- Releases
- New and returning issues per release. Readable stack traces from minified JavaScript, Android, iOS and Windows through source maps, ProGuard, dSYM and PDB.
- Team
- Roles, invitations and teams, for example one per client. Two-factor sign-in, passkeys and API tokens for CI.
- Interface
- German and English, light and dark. Command palette on ⌘K; j and k move through the list, e resolves an issue.
Where your data lives
Events, accounts and settings are stored on a server of Hetzner Online GmbH in Nuremberg, Germany. Hetzner is certified to ISO/IEC 27001. Fehlo uses no CDN, no Cloudflare and no tracking.
Before an event is stored, Fehlo removes the sender's IP address and filters out email addresses, passwords and tokens. This is on by default.
You sign the data processing agreement under Art. 28 GDPR online with NeuralMedic GmbH of Ingolstadt at launch. The service providers involved are listed under subprocessors. This website sets no cookies and loads nothing from other servers.
Fehlo and Sentry compared
Sentry is a good tool from the US. If your clients require a German provider, these are the differences.
| Fehlo | Sentry | |
|---|---|---|
| Provider | NeuralMedic GmbH, Ingolstadt | Functional Software, Inc., San Francisco |
| Errors, traces, logs | Germany | US, or EU region in Frankfurt |
| Accounts, project metadata, DSN keys, audit logs | Germany | may be stored in the US regardless of region1 |
| Status pages | included | not offered3 |
| AI help with fixes | fix prompt included | Seer: $40 per active contributor per month2 |
| Entry, paid | €9 a month, 100,000 events | $26 a month billed yearly, 50,000 errors2 |
For agencies
Agencies and software houses look after many projects for clients who expect a German data processor. For them, Fehlo has:
- Teams per client, each with its own projects and access. Your people see everything, the client only their own.
- A data processing agreement you can pass on to your clients (before launch).
- A monthly report per client with your logo: stability, fixed issues, uptime (in progress).
Pricing
Billed by events per month. Every plan includes issues, performance, logs, releases and email alerts; events are kept for 30 days.
| Plan | Events a month | Users | Also | Monthly | Yearly |
|---|---|---|---|---|---|
| Free | 5,000 | 1 | €0 | €0 | |
| Solo | 100,000 | 3 | Error explanations (soon) | €9 | €90 |
| Team | 500,000 | unlimited | Chat alerts, uptime, status pages | €29 | €290 |
| Agency | 2,000,000 | unlimited | Teams per client; client reports and 90-day retention (soon) | €79 | €790 |
| Dedicated | as needed | unlimited | Your own server in Germany, single sign-on, SLA | from €299 |
Questions
Does it really work with my existing Sentry setup?
Yes. Fehlo speaks the protocol of the sentry SDKs. You change the DSN; your code, SDK and sentry-cli stay as they are.
Where is my data stored?
On a server of Hetzner Online GmbH in Nuremberg, Germany. That covers events as well as accounts and settings.
Do I get a data processing agreement?
Yes, a DPA under Art. 28 GDPR with NeuralMedic GmbH. You can sign it online at launch.
What happens if I go over my quota?
Events are dropped gradually and you get an email. On a paid monthly plan you can allow pay as you go instead: €0.15 per 1,000 extra events, tiered down to €0.08, never beyond the monthly limit you set. Nothing is billed without your consent.
Does Fehlo store my users' IP addresses?
No. They are removed before an event reaches processing. Fehlo also filters email addresses, passwords and tokens out of events.
Can I delete data?
Yes: single issues, whole projects or the organisation, at any time and immediately.
Is Fehlo built on open source?
Yes. The engine is GlitchTip (MIT licence), which we have extended with features, fixes and our own interface. Details under open source licences.
Who is behind Fehlo?
NeuralMedic GmbH from Ingolstadt, Germany. We build data and AI platforms for German mid-sized companies.