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Lambda (AWS Serverless) vs DynamoDB

Lambda (AWS Serverless) logo

Lambda (AWS Serverless)

Cloud

Run code without thinking about servers

From
Free
Rated
-
Full reviewWebsite
DynamoDB logo

DynamoDB

Databases

AWS-only managed key-value and document database with fixed per-partition throughput limits and no ad hoc queries.

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Lambda (AWS Serverless) billed on two axes at once, $0.20 per million requests plus $0.0000166667 per GB-second of duration, so memory settings change the bill as much as traffic does; DynamoDB access patterns must be designed into the key schema before launch; a query nobody anticipated needs a new global secondary index, which is a full extra copy of the projected attributes billed as storage and as writes, or an offline migration.
  • They diverge on capability: Lambda (AWS Serverless) covers Function-as-a-Service, DynamoDB covers Managed and serverless.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Lambda (AWS Serverless) and DynamoDB actually diverge.

Attributes where Lambda (AWS Serverless) and DynamoDB differ
AttributeLambda (AWS Serverless)DynamoDB
PlatformsWeb, ApiAWS
CategoryCloudDatabases
Founded20142006

Identical on both: starting price (Free), pricing model (usage-based), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Lambda (AWS Serverless)

  • Function-as-a-Service
  • Event-driven execution
  • Auto-scaling
  • Pay-per-use
  • Multiple languages
  • Concurrency limits
  • Dead Letter Queues
  • Environment variables

Only in DynamoDB

  • Managed and serverless
  • Predictable latency
  • On-demand or provisioned capacity
  • Global secondary indexes
  • Transactions
  • DynamoDB Streams
  • Global tables
  • Point-in-time recovery

What people use each for

The jobs each tool is most often brought in to do.

Lambda (AWS Serverless)

  • Event-driven functions without managing serversnot DynamoDB
  • API backends behind API Gatewaynot DynamoDB
  • Processing S3, DynamoDB, SQS and Kinesis eventsnot DynamoDB
  • Scheduled jobs without a always-on instancenot DynamoDB
  • Edge compute through Lambda@Edgenot DynamoDB

DynamoDB

  • High-volume keyed workloads such as sessions, shopping carts, device state or user profiles where the access pattern is fixed and knownnot Lambda (AWS Serverless)
  • Traffic that spikes unpredictably, where on-demand capacity absorbs a burst without a capacity-planning exercisenot Lambda (AWS Serverless)
  • Serverless applications on Lambda, where an HTTP-based datastore avoids the connection pooling problem relational databases havenot Lambda (AWS Serverless)
  • Event or telemetry ingestion where writes vastly outnumber reads and each record is retrieved by a known identifiernot Lambda (AWS Serverless)

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Lambda (AWS Serverless)

  • Billed on two axes at once, $0.20 per million requests plus $0.0000166667 per GB-second of duration, so memory settings change the bill as much as traffic does
  • Provisioned concurrency, used to avoid cold starts, is charged separately at $0.0000041667 per GB-second whether or not the function runs
  • Ephemeral storage beyond the included 512 MB is metered
  • Lambda@Edge costs $0.60 per million requests, three times the standard request rate
  • VPC use and cross-region data transfer carry EC2 charges on top

DynamoDB

  • Access patterns must be designed into the key schema before launch; a query nobody anticipated needs a new global secondary index, which is a full extra copy of the projected attributes billed as storage and as writes, or an offline migration.
  • Global secondary indexes are eventually consistent and cannot be read strongly, so a read-after-write against an index can legitimately miss the item that was just written, and application code must be written to tolerate that.
  • Per-partition throughput is capped at roughly 3,000 read and 1,000 write units, so a hot key throttles even when the table has spare capacity overall, and the only real fix is changing the key design to spread the load.
  • Items are limited to 400 KB and query results paginate at 1 MB, so large or list-shaped data has to be split, offloaded to S3 with a pointer, or read through pagination loops that complicate every consumer.
  • It runs only on AWS and the API is proprietary rather than a standard, so moving the data layer means rewriting it; ScyllaDB's Alternator is the only meaningfully compatible target and it brings a much smaller ecosystem.

Pricing, plan by plan

Lambda (AWS Serverless)

Free
  • Free TierFree
    • 1M free requests/month
    • 400,000 GB-seconds/month
    • Always free

DynamoDB

Free
  • On-Demand Capacity$null/usage-based
    • Pay-per-request pricing with automatic scaling
    • Read: 0.5 RRU per 4 KB (eventually consistent), 1 RRU per 4 KB (strongly consistent), 2 RRU per 4 KB (transactional)
    • Write: 1 WRU per 1 KB
  • Provisioned Capacity$null/hourly
    • Fixed hourly charges based on reserved capacity
    • RCU rate: $0.00013 per hour (Standard)
    • WCU rate: $0.00065 per hour (Standard)
  • Standard Table Class Storage$0.25/per GB/month
    • $0.25 per GB/month after free tier
    • First 25 GB free per month (free tier)
  • Standard-Infrequent Access Table Class$0.1/per GB/month
    • $0.10 per GB/month

Which should you pick?

Choose Lambda (AWS Serverless) if

  • You need function-as-a-service.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want event-driven execution.
Lambda (AWS Serverless) review

Choose DynamoDB if

  • You need managed and serverless.
  • You want to start without paying.
  • You work on AWS.
  • You also want predictable latency.
DynamoDB review

Questions people ask

Is Lambda (AWS Serverless) or DynamoDB better?
Neither clearly leads. Lambda (AWS Serverless) starts at Free and DynamoDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Lambda (AWS Serverless) or DynamoDB?
Lambda (AWS Serverless) starts at Free and DynamoDB at Free.
Does Lambda (AWS Serverless) or DynamoDB run on more platforms?
Lambda (AWS Serverless) runs on Web, Api. DynamoDB runs on AWS.
Can I use Lambda (AWS Serverless) for free?
Both have a free tier, so you can try either at no cost before committing.
What is Lambda (AWS Serverless) best used for?
Lambda (AWS Serverless) is most often used for event-driven functions without managing servers, api backends behind api gateway, processing s3, dynamodb, sqs and kinesis events, scheduled jobs without a always-on instance. Of those, event-driven functions without managing servers and api backends behind api gateway are not what DynamoDB is typically brought in for.
What can Lambda (AWS Serverless) do that DynamoDB cannot?
Lambda (AWS Serverless) covers Function-as-a-Service, Event-driven execution, Auto-scaling, Pay-per-use. DynamoDB covers Managed and serverless, Predictable latency, On-demand or provisioned capacity, Global secondary indexes.

Answered from the vendors’ own pages

Lambda (AWS Serverless): Is there a free tier for AWS Lambda?

Yes. AWS Lambda offers a free tier including 1 million requests per month, 400,000 GB-seconds per month, and 100 GB monthly response streaming.

Source
DynamoDB: On-demand or provisioned capacity?

On-demand suits unpredictable or spiky traffic and removes capacity planning. Provisioned with autoscaling is considerably cheaper for steady high-volume workloads. Tables can be switched between them, though not arbitrarily often.

Lambda (AWS Serverless): How is AWS Lambda charged?

Lambda charges $0.20 per million requests. Duration charges are $0.0000166667 per GB-second for x86 (up to 6 billion GB-seconds/month in US East Ohio with tiered pricing). Ephemeral storage over the included 512 MB costs $0.0000000309 per GB-second. Provisioned Concurrency costs $0.0000041667 per GB-second with a 5-minute minimum.

Source
DynamoDB: Can I run DynamoDB outside AWS?

No. DynamoDB Local exists for development and testing only. For a production-compatible alternative elsewhere, ScyllaDB's Alternator implements the DynamoDB API, but it is a different system with a different ecosystem.

Lambda (AWS Serverless): What are Lambda Durable Functions pricing?

Lambda Durable Functions include operations at $8.00 per million (start execution, steps, waits). Data written costs $0.25 per GB. Data retention is $0.15 per GB-month with configurable 1-90 day retention (default 14 days).

Source
DynamoDB: Can I run ad hoc queries or analytics?

Not on the table itself. Scans are slow and expensive at scale. The usual pattern is to export to S3 or stream changes out and query them in Athena, Redshift or another analytical engine.

DynamoDB: Is single-table design necessary?

It is the pattern that gets the most from DynamoDB when access patterns are well known, because it lets related items be retrieved in one query. It also makes the model harder to evolve, so many teams reasonably choose multiple simpler tables and accept extra requests.

DynamoDB: What are the real limits I should design around?

400 KB per item, 1 MB per query or scan page, 100 items per transaction, roughly 3,000 read and 1,000 write units per partition, and eventual consistency on global secondary indexes.

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