Analytics Engine

An analytics engine binding accepts data points from Worker code through writeDataPoint. Use it when you need a local buffer of structured events during development or single-node runs. The buffer is process-local and capped at 1024 points; older points are dropped when the cap is exceeded.

type is analytics_engine. dataset and credential_scope are required. The hydrated object exposes provider.kind as "buffer" and provider.dataset as the configured dataset name.

Method

writeDataPoint(point?) appends one point. Optional fields are blobs, doubles, and indexes. Each missing field becomes an empty array. Peren stores a timestamp in milliseconds. The method returns no value.

Configure

Create fleet.toml and worker.js.

[node]
node_id = "00000000-0000-0000-0000-000000000001"
advertise_addr = "127.0.0.1:7000"
listen = "127.0.0.1:7000"

[bucket]
kind = "memory"

[mtls]
ca_cert_path = "./certs/ca.pem"
leaf_cert_path = "./certs/leaf-cert.pem"
leaf_key_path = "./certs/leaf-key.pem"

[[services]]
name = "api"
worker_bundle_path = "worker.js"
compatibility_date = "2026-01-01"

[services.bindings.ANALYTICS]
type = "analytics_engine"
dataset = "requests"
credential_scope = "analytics"

[[sockets]]
name = "public"
listen = "127.0.0.1:8080"
service = "api"

export default {
  async fetch(_request, env) {
    env.ANALYTICS.writeDataPoint({
      blobs: ["request"],
      doubles: [1.0],
      indexes: ["tenant"],
    });
    return Response.json({
      provider: env.ANALYTICS.provider.kind,
      dataset: env.ANALYTICS.provider.dataset,
    });
  },
};

Run and verify

peren devcert ./certs
peren dev fleet.toml

peren dev binds loopback listeners on port 0 and uses a memory bucket for that session. Call the public: URL it prints. 54321 below stands for that port. peren serve keeps the listen addresses and bucket kind from the file.

curl http://127.0.0.1:54321/

Expected JSON includes "provider":"buffer" and "dataset":"requests". There is no Worker API to read buffered points back from env.

Failure

Points beyond the 1024 cap are dropped from the front of the buffer without throwing. If you need durable or fleet-wide analytics retention, write to an external system instead of relying on this binding alone.

Related

• Bindings overview
• Workers