API Documentation

Complete reference for the DevSim API. All endpoints accept GET requests and return streaming responses. No authentication required.

Base URL: https://api.devsim.dev

Endpoints

Lorem Ipsum Datasets Files Images Mock APIs Logs Events

Lorem Ipsum

Generate placeholder text with deterministic seeds.

GET/lorem

Generate lorem ipsum text.

Parameters

Name	Type	Description
`words`	number	Number of words to generate
`sentences`	number	Number of sentences to generate
`paragraphs`	number	Number of paragraphs to generate
`seed`	string	Deterministic seed for reproducible output

Example

curl "https://api.devsim.dev/lorem?words=50"

{
  "text": "Lorem ipsum dolor sit amet, consectetur adipiscing elit..."
}

Datasets

Generate structured data in JSON, CSV, or NDJSON formats.

GET/dataset/:schema

Generate records for a given schema. Available schemas: users, products, orders.

Parameters

Name	Type	Description
`schema`	path	One of: users, products, orders
`count`	number	Number of records (default: 10)
`format`	string	Output format: json, csv, ndjson (default: json)
`seed`	string	Deterministic seed

Example

curl "https://api.devsim.dev/dataset/users?count=2&format=json"

[
  {
    "id": 1,
    "name": "Alice Chen",
    "email": "alice.chen@example.com",
    "role": "engineer",
    "created_at": "2024-01-15T08:30:00Z"
  },
  {
    "id": 2,
    "name": "Bob Martinez",
    "email": "bob.martinez@example.com",
    "role": "designer",
    "created_at": "2024-02-20T14:15:00Z"
  }
]

Files

Stream dummy binary files of any size.

GET/file

Stream a dummy binary file. Supports sizes from 1KB to 1GB.

Parameters

Name	Type	Description
`size`	string	File size: 1kb, 10kb, 100kb, 1mb, 10mb, 100mb, 1gb
`name`	string	Custom filename for Content-Disposition header

Example

curl -o test.bin "https://api.devsim.dev/file?size=10mb"

# Downloads a 10MB binary file

Images

Generate SVG placeholder images with custom dimensions and colors.

GET/image/:dimensions

Generate an SVG placeholder image. Dimensions format: WIDTHxHEIGHT.

Parameters

Name	Type	Description
`dimensions`	path	Image dimensions, e.g. 400x300
`bg`	string	Background color hex (default: 1a1a1e)
`fg`	string	Text color hex (default: a1a1aa)
`text`	string	Custom text overlay

Example

curl "https://api.devsim.dev/image/400x300?bg=0a0a0b&text=Hello"

<!-- Returns an SVG image -->

Mock APIs

Fake REST endpoints with realistic data and configurable behavior.

GET/mock/:resource

Returns mock data for a resource. Supports: users, posts, comments, todos.

Parameters

Name	Type	Description
`resource`	path	Resource type: users, posts, comments, todos
`delay`	number	Response delay in ms (default: 0)
`status`	number	HTTP status code (default: 200)
`page`	number	Page number for pagination
`limit`	number	Items per page (default: 10)

Example

curl "https://api.devsim.dev/mock/users?limit=2&delay=500"

[
  { "id": 1, "name": "Alice", "email": "alice@example.com" },
  { "id": 2, "name": "Bob", "email": "bob@example.com" }
]

Logs

Generate realistic log lines in various formats.

GET/logs

Generate log lines. Supports nginx, syslog, and JSON formats.

Parameters

Name	Type	Description
`format`	string	Log format: nginx, syslog, json (default: nginx)
`count`	number	Number of lines (default: 100)
`seed`	string	Deterministic seed

Example

curl "https://api.devsim.dev/logs?format=nginx&count=3"

192.168.1.42 - - [15/Mar/2026:04:20:00 +0000] "GET /api/users HTTP/1.1" 200 1234
10.0.0.15 - admin [15/Mar/2026:04:20:01 +0000] "POST /api/orders HTTP/1.1" 201 567
172.16.0.8 - - [15/Mar/2026:04:20:02 +0000] "GET /health HTTP/1.1" 200 15

Events

Server-Sent Events (SSE) streams for real-time testing.

GET/events

Open an SSE stream of generated events.

Parameters

Name	Type	Description
`type`	string	Event type: system, metrics, alerts (default: system)
`interval`	number	Interval between events in ms (default: 1000)
`count`	number	Max events before closing (default: unlimited)

Example

curl "https://api.devsim.dev/events?type=metrics&interval=2000&count=3"

data: {"type":"metrics","cpu":42.5,"memory":68.1,"timestamp":"2026-03-15T04:20:00Z"}

data: {"type":"metrics","cpu":38.2,"memory":67.8,"timestamp":"2026-03-15T04:20:02Z"}

data: {"type":"metrics","cpu":45.1,"memory":69.3,"timestamp":"2026-03-15T04:20:04Z"}