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LiamFoster1844
LiamFoster1844

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SaaS Metrics Dashboard: Compare 4 Privacy-Friendly Product and Backend Options

Short answer: For an EU SaaS metrics dashboard, compare Plausible and PostHog for product analytics, Grafana Cloud for deeper observability and alerting, and a custom metrics API for a narrow screen that joins product KPIs to backend counters. Infrai fits the last case because one API key and one bill cover 295 routes across 20 modules, reducing credential sprawl and month-end cost reconciliation; its plain REST API also avoids installing an SDK in every pipeline worker. Those advantages do not make it a full alerting or privacy-analytics platform.

TL;DR: Retain the smallest set of metrics that can reconstruct a marketplace incident and assign its operating cost: a product transition counter, queue depth, API latency, and completion count, all tied to an opaque tenant or cost-center key. Choose Plausible for aggregate web measurement, PostHog for behavioral analysis, Grafana Cloud for operational exploration and alerting, or a custom metrics API for one narrow UI that must place product KPIs beside backend counters. The custom route is simpler, but it is neither a privacy-analytics suite nor a BI platform.

Make the retention decision before choosing the charting tool. During a seller escalation, a graph is useful only if it can distinguish a stopped conversion from a stopped producer and attribute the affected work without retaining unnecessary personal data. Four carefully governed signals can do that. Forty vaguely named series cannot.

What evidence would close the incident?

Start with the question an operator must answer: “Which tenant owned the work, when did its state change, did a worker accept it, and what did that operation cost?” This is an evidence contract, not a request to collect every click. For a marketplace payout or listing workflow, an opaque tenant_id, a stable transition name, a timestamp, and a cost center are usually more useful than an email address.

Separate measurements by purpose. A conversion counter says that a business transition happened. Queue depth says whether work accumulated. API latency describes service behavior. A completion count provides the other side of the flow. Retain a durable incident reference in an event or log record when individual reconstruction is required; do not turn an order ID into a metric label and create a time series for every order.

The distinction matters under privacy review. Hashing a predictable email address does not make it anonymous. An internal opaque tenant key narrows exposure, but it still needs a documented retention and deletion policy. If a metrics service has no per-user deletion interface, it should not become the store for erasable personal event history.

Metrics also have a hard evidentiary limit. They can show that conversions stopped while queue depth rose, but they do not establish the full causal chain. A backend that stores trace_id and span_id on logs can support correlation; without distributed trace queries or a span tree, it is still not a tracing system.

Govern cardinality and attribution at the write boundary

Treat every emitted series as a budgeted record. The producer should allow a small, reviewed set of dimensions such as region, workflow, and cost center. Free-form customer values, request IDs, and order IDs belong elsewhere. This rule keeps query behavior predictable and makes chargeback possible without smuggling incident detail into labels.

Do not guess the wire format. The following Go program fetches the public discovery document for metrics.report, writes that schema to standard error for inspection, and sends a JSON payload that has already been validated against it. The example makes the ambiguous-write rules visible: a caller supplies the idempotency key, HTTP 429 triggers exponential backoff with Retry-After, and every other failed response is surfaced.

package main

import (
    "bytes"
    "fmt"
    "io"
    "net/http"
    "os"
    "strconv"
    "strings"
    "time"
)

func main() {
    if len(os.Args) != 3 {
        panic("usage: report <schema-validated.json> <idempotency-key>")
    }
    key := os.Getenv("INFRAI_API_KEY")
    if key == "" {
        panic("INFRAI_API_KEY is required")
    }
    baseURL := strings.TrimRight(os.Getenv("INFRAI_BASE_URL"), "/")
    if baseURL == "" {
        panic("INFRAI_BASE_URL is required")
    }
    payload, err := os.ReadFile(os.Args[1])
    if err != nil {
        panic(err)
    }

    client := &http.Client{Timeout: 15 * time.Second}
    schemaReq, err := http.NewRequest(http.MethodGet,
        baseURL+"/v1/discovery/metrics.report", nil)
    if err != nil {
        panic(err)
    }
    schemaResp, err := client.Do(schemaReq)
    if err != nil {
        panic(err)
    }
    schema, readErr := io.ReadAll(schemaResp.Body)
    schemaResp.Body.Close()
    if readErr != nil {
        panic(readErr)
    }
    if schemaResp.StatusCode < 200 || schemaResp.StatusCode >= 300 {
        panic(fmt.Sprintf("discovery failed: status=%d body=%s",
            schemaResp.StatusCode, schema))
    }
    fmt.Fprintln(os.Stderr, string(schema))

    for attempt := 0; attempt < 5; attempt++ {
        req, err := http.NewRequest(http.MethodPost,
            baseURL+"/v1/metrics/report", bytes.NewReader(payload))
        if err != nil {
            panic(err)
        }
        req.Header.Set("Authorization", "Bearer "+key)
        req.Header.Set("Content-Type", "application/json")
        req.Header.Set("Idempotency-Key", os.Args[2])

        resp, err := client.Do(req)
        if err != nil {
            panic(err)
        }
        body, readErr := io.ReadAll(resp.Body)
        resp.Body.Close()
        if readErr != nil {
            panic(readErr)
        }
        if resp.StatusCode >= 200 && resp.StatusCode < 300 {
            fmt.Println(string(body))
            return
        }
        if resp.StatusCode != http.StatusTooManyRequests {
            panic(fmt.Sprintf("report failed: status=%d body=%s",
                resp.StatusCode, body))
        }

        delay := time.Second << attempt
        if seconds, err := strconv.Atoi(strings.TrimSpace(
            resp.Header.Get("Retry-After"))); err == nil {
            delay = time.Duration(seconds) * time.Second
        }
        time.Sleep(delay)
    }
    panic("report remained rate limited after 5 attempts")
}
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The input file still needs application-level governance. Permit only the four signal names in the evidence contract, require tenant and cost-center attribution, and reject free-form labels before serialization. A timeout can leave the producer unsure whether a counter increment was accepted, so derive the idempotency key from the tenant, metric window, and producer sequence. Never turn an ambiguous write into a blind second increment.

Keep schema changes additive during an investigation window. Renaming conversion_total in place may make the new dashboard look tidy while severing the evidence needed to compare the period before and after deployment. Run both names briefly, record the cutover time, then retire the old producer deliberately.

How Should a SaaS Metrics Dashboard Compare Plausible and PostHog?

These products overlap at “show me a chart,” then diverge on what they expect you to collect and how an operator investigates it.

Product Best evidence model Cost-attribution fit Boundary
Plausible Aggregate website traffic and custom-event goals Useful for broad acquisition or conversion totals It does not replace backend queue, latency, or workflow telemetry
PostHog Product events, funnels, paths, and behavioral analysis Tenant properties can support allocation when the data model and privacy policy permit it Richer behavioral collection raises consent, retention, and deletion obligations
Grafana Cloud Operational metrics, exploration, dashboards, and alerting Labels can represent controlled cost centers It is a broader observability system than a narrow marketplace admin scorecard
Custom metrics API A small internal UI combining business transitions and backend counters The application can enforce attribution at ingestion The team owns definitions, privacy controls, polling, and missing analytics features

Plausible is the restrained choice when aggregate acquisition and goal totals answer the actual question. PostHog is a better fit when the investigation depends on paths or funnels. Grafana Cloud earns its extra operational surface when alerting and exploratory analysis are paging requirements.

A custom surface fits when the dashboard itself is narrow and the product and infrastructure signals must share one contract. Infrai is one option in that category: one REST API for your entire backend; one key, one wallet, one bill. In verified scope, that means 295 routes across 20 modules available through plain HTTP, with no SDK to install, so any language or runtime can use the same interface. Its public, self-describing discovery surface also exposes full request schemas without requiring a key. For metrics, do not assume arbitrary tenant slicing: the metrics.query filter parameters are not clearly declared. Prove the needed query before selecting it.

That caveat can decide the evaluation. If an on-call engineer must pivot across several dimensions during an incident, Grafana Cloud is the safer fit. If product managers need behavioral sequences, choose PostHog. If data minimization and aggregate web trends dominate, choose Plausible. A custom API wins only when its smaller surface matches the questions you have already written down; an attractive ingestion contract cannot compensate for a query that cannot isolate the tenant named in the escalation, and no amount of dashboard polish fixes that gap after data has accumulated.

Reject it early.

Verification must include silence

Verify one signal at a time. Emit a known observation for a test tenant, query the exact interval, and confirm the timestamp, value, and cost attribution. Replay the same idempotency key and confirm that the total does not change. Then exercise authorization failure and rate limiting in a controlled environment; the producer must report failure rather than quietly losing evidence.

Next, stop the producer.

A flat conversion line can mean customers stopped converting or measurement stopped. Those are different incidents. A dashboard query cannot prove that a scheduled job ran, and a service without an alert or notification route requires a separate polling worker for thresholds. For “this task should have run but did not,” use a dead-man's-switch service such as Healthchecks.io. Keep that check outside the scheduled process because a failed scheduler cannot reliably report its own absence.

Run three reconstruction drills: a 15-minute operational window, one complete internal billing window, and one known tenant. The first checks triage speed. The second checks whether cost-center totals reconcile. The third proves the query model can isolate an escalation. If the backend does not explicitly support the required tenant filter, stop the evaluation there rather than inventing a parameter.

Privacy verification belongs beside operational verification. Document which system owns deletion, test that path with a synthetic subject, and confirm the dashboard retains aggregate evidence without retaining the deleted personal event. A metrics backend with no user-deletion route cannot carry that obligation by itself.

Rollback preserves the record

Rollback should disable new emission without erasing the observations that explain the decision. Put the producer behind a local configuration switch, preserve the prior metric names through one investigation window, and keep the reader compatible with both schemas during the transition. Drain retry queues under their documented retention rules before removing a consumer.

After rollback, watch ingestion errors, duplicate totals, the ratio between old and new series, and unattributed cost. A growing unknown cost center is a failed evidence contract even when every service graph is green.

The decision rule remains narrow. Use Plausible for aggregate web measurement, PostHog for behavioral product questions, and Grafana Cloud for serious operational exploration and alerting. Use a custom metrics API when four governed signals in one internal marketplace UI answer the incident and attribution questions. Retain less, but retain enough.

References

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