Developer Onboarding Checklist for Distlang Metrics 2026

Why a Specific Onboarding Checklist Matters

Up to 20% of staff turnover happens within the first 45 days, according to research published by Harvard Business Review. For developers, the stakes are even more pointed: a study in ACM Queue found that better developer experience directly improves productivity, learning, and innovation. Generic onboarding processes that say “read the wiki for a week” don’t cut it.

Practitioners on Reddit consistently report that the biggest first-week blockers are access and environment setup, not the code itself. One thread in r/programming emphasized that the best onboarding feels like guided contribution, with a new hire shipping something small in their first week rather than passively reading docs. Pre-provisioning accounts and credentials before day one avoids the stalled starts that kill momentum.

That’s exactly what a developer onboarding checklist for Distlang Metrics should deliver: a short, ordered sequence where each step is verifiable, each task builds on the last, and the new developer sees real data on a real dashboard within hours.

What “Developer Onboarding Checklist for Distlang Metrics” Means

A developer onboarding checklist for Distlang Metrics is an ordered set of tasks new team members follow to:

  1. Get access to Distlang Metrics (account, API token, secrets)
  2. Instrument application code with counters and histograms using the @distlang/client JavaScript library
  3. Flush metrics correctly in serverless runtimes (Cloudflare Workers, Vercel)
  4. Confirm data appears on the hosted dashboard at dash.distlang.com

Distlang Metrics is API-first with a lightweight JavaScript client and a single long-lived API token per account. The Distlang Metrics quickstart describes the system as designed for teams that want metrics “with just code” and minimal ops overhead, especially on serverless and edge runtimes where agents and sidecars aren’t an option.

Pre-Day-1: Account and Access Setup

Complete these before the new developer’s first day. Experienced devs on Reddit stress that pre-provisioning access is the single highest-leverage onboarding investment.

Create the Distlang account and get the API token

Go to dash.distlang.com and create an account. Navigate to the Auth page and generate your API token. The token is shown once, so copy it immediately and store it in your team’s secrets manager.

Acceptance criterion: Token copied and stored securely. The new developer will never need to see the raw value again after initial setup.

Store the token as an environment secret

For Cloudflare Workers, use wrangler secret put DISTLANG_ACCESS_TOKEN. For Vercel, add it as a project environment variable. Either way, the token should be referenced in code as DISTLANG_ACCESS_TOKEN, not hardcoded. The Distlang API tokens documentation covers token lifecycle and rotation.

Acceptance criterion: Running the app locally or in staging can access the token from the environment without any plaintext values in source control.

Day 1, Step 1: Install the Client and Create a Recorder

Install the package:

npm install @distlang/client

Then initialize a recorder with a stable metricSet name and definitions for at least two metrics: a request counter and a latency histogram.

import { createRecorder } from "@distlang/client";

const metrics = createRecorder({
  accessToken: env.DISTLANG_ACCESS_TOKEN,
  metricSet: "my-api",
  definitions: {
    requestCount: { type: "counter" },
    latencyMs: { type: "histogram" },
  },
});

The metricSet name groups your metrics on the dashboard. Keep it stable across deploys. Changing it creates a new dashboard.

Acceptance criterion: Recorder created without import or runtime errors. The flush method is available on the recorder object.

Day 1, Step 2: Instrument a Minimal RED Baseline

The RED method (Rate, Errors, Duration) gives request-driven services exactly the three signals they need on day one. It maps to Google’s Four Golden Signals and gives new developers a clear answer to “what should I instrument first?”

Add two lines inside your request handler:

metrics.requestCount.inc();

const start = Date.now();
// ... handle request ...
metrics.latencyMs.observe(Date.now() - start);

That’s it for the baseline. Rate comes from the counter’s increase over time. Duration comes from the histogram observations. Errors come later as a stretch goal (separate counter with a status label).

Acceptance criterion: Every request increments the counter and records a latency observation. The new developer can explain why these two metrics were chosen.

Day 1, Step 3: Flush Correctly in Your Runtime

This is the step most generic onboarding guides miss entirely, and it’s the one that causes the most confusion for developers new to serverless. In short-lived serverless handlers, the runtime can terminate your function the moment it returns a response. If you haven’t flushed your metrics by then, they’re lost.

Cloudflare Workers: ctx.waitUntil

Cloudflare Workers provide ctx.waitUntil() to extend a Worker’s lifetime for background tasks after the response has been sent. This is the correct place for metrics flush. The Cloudflare Workers context documentation explains the mechanism in detail.

export default {
  async fetch(request, env, ctx) {
    const metrics = createRecorder({
      accessToken: env.DISTLANG_ACCESS_TOKEN,
      metricSet: "my-api",
      definitions: {
        requestCount: { type: "counter" },
        latencyMs: { type: "histogram" },
      },
    });

    const start = Date.now();
    metrics.requestCount.inc();

    // ... build your response ...
    const response = new Response("OK");

    metrics.latencyMs.observe(Date.now() - start);
    ctx.waitUntil(metrics.flush());

    return response;
  },
};

The Cloudflare Workers metrics example in the Distlang docs provides the full working pattern.

Acceptance criterion: The Worker compiles and deploys without errors. No “Illegal invocation” issues. Metrics appear on the dashboard after a few requests.

Vercel and Next.js: after()

Next.js provides the after() function, which uses waitUntil under the hood on Vercel’s runtime to extend the handler’s lifetime.

import { after } from "next/server";

export async function GET(request) {
  const metrics = createRecorder({
    accessToken: process.env.DISTLANG_ACCESS_TOKEN,
    metricSet: "my-api",
    definitions: {
      requestCount: { type: "counter" },
      latencyMs: { type: "histogram" },
    },
  });

  const start = Date.now();
  metrics.requestCount.inc();

  // ... build your response ...

  metrics.latencyMs.observe(Date.now() - start);
  after(async () => metrics.flush());

  return new Response("OK");
}

The Next.js after() metrics example in the Distlang Vercel guide covers this pattern with more context.

Acceptance criterion: Route handler returns immediately. Metrics appear on the dashboard within minutes.

Day 1, Step 4: Labeling and Cardinality Guardrails

Labels add dimensions to your metrics. They’re powerful and dangerous. A label with unbounded values (like a raw user ID or full URL path) will create a unique time series for every distinct value, and your metric cardinality will explode. The Prometheus documentation on metric types and best practices consistently warn against this.

Rules for new developers

Use only bounded labels. Good examples: method (GET, POST, PUT, DELETE), statusClass (2xx, 3xx, 4xx, 5xx), route (a template like /api/users/:id, not the actual path /api/users/abc123).

Never use as labels: user IDs, session tokens, raw URLs, request bodies, timestamps, or any value that grows with traffic.

Enforce through code review. Add a note in your PR template or linting configuration that flags unbounded label values. This is especially important during onboarding because new developers often add high-cardinality labels thinking they’re being thorough.

// Good: bounded labels
metrics.requestCount.inc({ method: "GET", statusClass: "2xx" });

// Bad: unbounded label, creates a new series per user
metrics.requestCount.inc({ userId: request.userId });

Acceptance criterion: The new developer’s first metrics PR uses only bounded labels. A reviewer has checked for cardinality risks.

Day 1, Step 5: Verify Ingestion on the Dashboard

Open the Dashboards section at dash.distlang.com. Distlang auto-generates a dashboard for each metricSet, so you should see your metric set name with charts showing recent activity. The free tier provides 500k rows per month with 7-day retention, which is more than enough for onboarding and initial development. Read more about the setup-to-dashboard path in the metrics quickstart guide.

Acceptance criterion: The dashboard shows your requestCount and latencyMs with real data points. Take a screenshot and attach it to your onboarding PR.

This milestone is your Time-to-First-Dashboard (TTFD). Aim to hit it within day one. It’s the single clearest signal that a new developer’s onboarding is on track.

First-Week Targets

Merge a PR that touches metrics code

Practitioners on Reddit are clear on this: the best onboarding gets new hires to a real contribution within the first week. A PR that adds or modifies metric instrumentation is ideal because it’s low-risk, immediately verifiable on the dashboard, and teaches the developer your team’s conventions for naming, labeling, and flushing.

Pair programming works well here. One experienced developer on r/ExperiencedDevs noted that pairing on a small, low-risk task during onboarding builds confidence and surfaces gotchas early, before they become habits.

Acceptance criterion: PR merged that touches the recorder, a metric definition, or labels. Dashboard screenshot attached showing the new or modified metric.

Stretch goals for the motivated

  • Add an error counter: Create a separate counter (e.g., errorCount) and increment it on non-2xx responses. This completes the “E” in RED.
  • Add a status label: Use statusClass (2xx, 3xx, 4xx, 5xx) as a label on your request counter.
  • Verify percentiles: Check that the latency histogram on the dashboard shows p50, p95, and p99 values. Histograms are preferred over summaries for latency because histograms can be aggregated across instances while summaries cannot.

Acceptance criterion: Distinct success/failure counters visible. Latency p95 readable on the dashboard.

Common Pitfalls and How to Fix Them

Forgetting to flush in short-lived handlers

The most common mistake. Without an explicit flush() call inside ctx.waitUntil or after, metrics buffer in memory and then vanish when the runtime kills the function.

Fix: Always wire metrics.flush() to the runtime’s post-response lifecycle. Test by deploying and checking the dashboard, not just by running locally.

High-cardinality labels

Adding userId, full URL paths, or request IDs as labels. This looks helpful during development but creates thousands or millions of unique time series.

Fix: Replace with bounded categories. Use route templates, HTTP method names, and status classes.

Blocking the response while flushing

Calling await metrics.flush() before returning the response adds latency to every request. Both Cloudflare Workers and Vercel provide background execution primitives specifically to avoid this.

Fix: Use ctx.waitUntil(metrics.flush()) on Workers and after(async () => metrics.flush()) on Vercel. The response returns immediately while the flush completes in the background.

Exceeding platform time limits

Cloudflare Workers have a roughly 30-second post-response window for waitUntil tasks, per Cloudflare’s best practices documentation. If your flush is slow (large batch, network issues), it could be killed.

Fix: Keep flush payloads small. The Distlang client buffers efficiently, but avoid accumulating thousands of observations before flushing.

Non-JavaScript Stacks

Not every service is written in JavaScript. If your team runs Python, Go, Rust, or anything else, the Distlang Metrics HTTP API accepts bearer-token-authenticated writes over standard HTTP. Any language that can make an HTTP POST can send metrics.

Acceptance criterion: A curl call with Authorization: Bearer <token> successfully writes a test metric row. The dashboard reflects it.

Printable Checklist Summary

Use this as a quick reference. Each item maps to the detailed sections above.

  • [ ] API token created at dash.distlang.com and stored as an environment secret
  • [ ] @distlang/client installed; recorder created with a stable metricSet and metric definitions
  • [ ] RED baseline instrumented: requestCount.inc() and latencyMs.observe() on every request
  • [ ] Flush wired to runtime lifecycle: ctx.waitUntil(metrics.flush()) on Workers or after(async () => metrics.flush()) on Vercel
  • [ ] Labels are bounded only (method, statusClass, route template); no user IDs or raw URLs
  • [ ] Dashboard visible at dash.distlang.com with activity for your metric set; screenshot saved
  • [ ] First PR merged within week 1 that touches metrics code (paired if possible)
  • [ ] Stretch: error counter added, status labels applied, p95 latency visible on dashboard

If you’re starting from scratch, the Distlang Metrics quickstart walks through the full flow in about ten minutes.

FAQ

Do I need to block the response while flushing metrics?

No. Use ctx.waitUntil() on Cloudflare Workers or after() on Vercel/Next.js so the flush completes after the response has already been sent. This keeps response latency low while still ensuring metrics are delivered.

What’s the difference between counters and histograms?

Counters track cumulative totals (like total requests). Histograms capture distributions (like request latency across buckets). Use counters for “how many” and histograms for “how long” or “how big.” Histograms are generally preferred over summaries because histograms can be aggregated across instances while summaries cannot.

Can I send metrics from non-JavaScript code?

Yes. The Distlang Metrics API accepts standard HTTP writes with bearer token authentication. Any language or platform that can make HTTP requests can send metrics.

What labels should I avoid?

Anything unbounded. User IDs, session tokens, raw URL paths, and timestamps all create unique time series for every distinct value. Stick to bounded categories like HTTP method, status class (2xx/3xx/4xx/5xx), and route templates.

How quickly should a new developer see their first dashboard?

Aim for same-day. The Distlang onboarding checklist is designed so Time-to-First-Dashboard stays under a few hours, assuming access and secrets are pre-provisioned. If it’s taking longer than a day, something in the checklist is blocked.

What does the free tier include?

The free plan at dash.distlang.com includes 500k rows per month, 7-day retention, unlimited metric sets, and AI chart suggestions. That’s plenty for onboarding, development, and small production workloads.

How do I rotate the API token?

Distlang uses one long-lived token per account. Rotate it only when needed (compromised credential, team member departure). When you create a new token, copy it immediately and update your environment secrets across all deployments. The token management docs cover the full process.

What is the RED method and why start there?

RED stands for Rate, Errors, and Duration. It’s a focused framework for request-driven services, closely related to Google’s Four Golden Signals. Starting with RED gives new developers exactly three things to instrument on day one, which is enough to be useful without being overwhelming.