LLM Best Practices

Cloudflare Workers vs AWS Lambda

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Overview

Pick Workers for per-request logic that should run close to users; pick Lambda for heavier compute and for functions tied to AWS services or a VPC. Workers run in V8 isolates across Cloudflare’s network (348 cities); Lambda runs in microVMs in the AWS Regions you choose. Limits and prices below were checked on 2026-10-01.

Comparison

DimensionCloudflare WorkersAWS Lambda
PlacementCloudflare’s global network by defaultChosen AWS Regions
Memory128 MB per isolate128 to 10,240 MB (about one vCPU at 1,769 MB)
Time limitCPU time: 10 ms per invocation on Free; paid default 30 seconds, up to 5 minutes (15 minutes for Cron Triggers and Queue consumers); no limit on wall-clock duration15 minutes per invocation (up to 90 minutes for Lambda Managed Instances async and event-source invocations)
BillingFree: 100,000 requests per day. Paid: 0.30 per million requests and $0.02 per million CPU-ms; duration is not billed$0.20 per million requests plus GB-seconds; 1M requests and 400,000 GB-seconds free per month; init-phase time is billed
LanguagesJavaScript, TypeScript, Wasm; Python Workers in beta; nodejs_compat is on by default for compatibility dates from 2026-08-04Node.js, Python, Java, .NET, Ruby, custom runtimes, container images up to 10 GB
PayloadsHTTP-centric; large bodies through R2 or streaming6 MB synchronous request and response; 200 MB streamed response
Private resourcesHyperdrive and TunnelNative VPC attachment
TriggersHTTP, Cron, Queues, Durable ObjectsS3, SQS, DynamoDB Streams, EventBridge, API Gateway, and many more

Pick Workers when

Pick Workers for request-scoped logic on the hot path.

  • Auth checks, redirects, header rewrites, geolocation routing, A/B tests, API gateways, and SSR close to users.
  • I/O-bound handlers: waiting on upstream calls costs nothing in duration, because only CPU time is billed.
  • Storage bindings (KV, R2, D1, Durable Objects, Queues) with no network setup. See cloudflare-kv and cloudflare-r2.
  • Workloads outside the isolate limits can use Cloudflare Containers, which are driven from Workers.

Pick Lambda when

Pick Lambda for heavier or AWS-coupled functions.

  • Gigabytes of memory, up to 15 minutes of runtime, native dependencies, or container images.
  • Direct access to RDS, ElastiCache, and private services inside a VPC.
  • Triggers from S3, DynamoDB Streams, SQS, EventBridge, or Kinesis.
  • Longer or multi-step jobs: Lambda Managed Instances, durable functions, and Lambda MicroVMs (up to 8 hours per MicroVM) exist for cases the standard model does not fit.

Port from Lambda to Workers

Rewrite handlers to the Workers fetch handler; this is a rewrite, not a redeploy. Replace native modules, move VPC database access to Hyperdrive, split over-limit work into Queues or Containers, and keep AWS-event-driven jobs on Lambda. See aws-vs-cloudflare for the platform decision.

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