ChartQuery Ruby SDK

The official Ruby SDK for the ChartQuery chart and QR code API.

Generate chart images, diagrams, barcodes, QR codes and thermal labels on demand. PNG, SVG or PDF output.

The SDK exposes 20 methods, one per documented endpoint, plus a generic request. It only uses the Ruby standard library.

Requirements

• Ruby 3.1 or newer

Installation

gem install chartquery

Or in your Gemfile:

gem "chartquery"

Get your API key

Sign up for ChartQuery or sign in, then copy your API key from the dashboard. The client reads ENV["CHARTQUERY_API_KEY"] when no key is passed.

Quick start

require "chartquery"

client = ChartQuery::Client.new(api_key: ENV.fetch("CHARTQUERY_API_KEY"))
response = client.chart_ai(prompt: "Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18")
puts response.data

Keyword arguments use the parameter names of the API reference. Unknown names raise ChartQuery::SerializationError; use request for undocumented parameters.

Binary responses

Endpoints that can return a file (image, PDF…) return a JsonResponse or a BinaryResponse:

response = client.qrcode(data: "https://chartquery.com", format: "png")
response.save("qrcode.png") if response.binary?

Async jobs

Any call accepts is_async: true (useful past the 60-second server limit): the response is then a job_id. wait_for_job polls GET /v1/jobs/{id} until a terminal status (CompletedJob, Error, NotFound, BadRequest):

submitted = client.chart_ai(prompt: "Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18", is_async: true)
job = client.wait_for_job(submitted.data["job_id"]) { |j| puts "#{j['status']} #{j['progress']}%" }
puts job.data

GET or POST

Methods use GET when the endpoint supports it (query string). POST sends the same parameters as JSON:

client.barcode(data: "test", request_options: { method: "POST" })

nil values are omitted, false and 0 are sent, and arrays repeat the parameter name.

Any endpoint

response = client.request("GET", "/v1/usage")

Errors

begin
  client.chart_ai(prompt: "Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18")
rescue ChartQuery::APIError => e
  warn "HTTP #{e.status}: #{e.message}"
end

Error	When
ChartQuery::ConfigurationError	Missing API key, invalid options or unsupported method.
ChartQuery::SerializationError	A required parameter is missing, unknown or can't be sent.
ChartQuery::TransportError	Network failure or timeout.
ChartQuery::APIError	Non-2xx status (status, error_message, response_body, raw_response).
ChartQuery::ResponseDecodingError	A success response could not be decoded.

All of them inherit from ChartQuery::Error.

Retries

Requests are retried up to 3 times after a network error, a 408, 500, 502, 503 or 504, or a rate limit — which the API returns as 401 (or 429) with a Rate limit exceeded message. Per-key quota errors (…: quota daily) are not retried, nor are 400, 402, 404 or client-side timeouts. The delay starts at 1 second and grows 1.5× per retry (capped at 30 seconds); a Retry-After header wins.

client = ChartQuery::Client.new(max_retries: 5, retry_delay: 0.5)
client.chart_ai(prompt: "Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18", request_options: { max_retries: 0 }) # one request without retries

Batch requests

batch runs the block for every item on 10 threads (concurrency:) and returns one BatchResult per item, in input order. A failing item never stops the others.

inputs = ["Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18", "Market share as a pie chart: A 40, B 35, C 25"]
results = client.batch(inputs, concurrency: 5) { |value| client.chart_ai(prompt: value) }
results.each do |result|
  if result.ok?
    puts result.value.data
  else
    warn "#{inputs[result.index]}: #{result.error.message}"
  end
end

Constant	Default	Description
ChartQuery::Client::DEFAULT_CONCURRENCY	10	Tasks run at the same time by batch
ChartQuery::Client::DEFAULT_TIMEOUT	120	Request timeout (seconds)
ChartQuery::Client::MAX_RETRIES	3	Retry attempts after a network error, a 408/5xx or a rate limit
ChartQuery::Client::RETRY_BACKOFF_FACTOR	1.5	Exponential backoff multiplier
ChartQuery::Client::DEFAULT_RETRY_DELAY	1.0	Delay before the first retry (seconds)

Timeouts and custom transports

client = ChartQuery::Client.new(timeout: 60) # seconds, default 120
client.chart_ai(prompt: "Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18", request_options: { timeout: 30 })

A transport is any object with call(method:, url:, headers:, body:, timeout:) returning [status, headers, body]; the default is ChartQuery::NetHTTPTransport.

Endpoints

20 methods, generated from the OpenAPI document.

Method	HTTP	Description
barcode	GET / POST /v1/barcode	Generate a barcode image via GET. Output: SVG (default) or PNG. Supports 25+ formats: EAN-13, Code 128, ITF-14, GS1-128, postal codes and m…
chart	GET / POST /v1/chart	Render a Chart.js image via GET. Pass the full chart object as URL-encoded JSON in query. Prefer format png for ChatGPT. POST sends the sam…
chart_ai	GET / POST /v1/chart/ai	Describe a chart in plain English via GET and get a rendered image back. Powered by AI.
chart_render	GET /v1/chart/render/{id}	Render a previously saved chart by ID. Public, no API key required. Supports URL overrides for templates (?data1=, ?labels=, ?title=…).
chart_view	GET /v1/chart/view/{id}	View a previously saved chart as an interactive HTML page. Public, no API key required. Iframe-embeddable.
diagram	GET / POST /v1/diagram	Render a diagram via GET. Use type (mermaid, d2, …), query (source code), and format=png for ChatGPT. POST uses diagram_type and diagram_so…
diagram_ai	GET / POST /v1/diagram/ai	Describe a diagram in plain English via GET and get a rendered image back. Powered by AI.
diagram_render	GET /v1/diagram/render/{id}	Render a previously saved diagram by ID. Public, no API key required. Supports ?format= and ?query= overrides.
diagram_view	GET /v1/diagram/view/{id}	View a previously saved diagram as an HTML page. Public, no API key required. Iframe-embeddable with inline SVG rendering.
jobs	GET /v1/jobs/{id}	Poll the status, progress (0–100) and result of a job started with is_async=true. Polling is free. Poll until status is terminal: Completed…
label	GET / POST /v1/label	Preview a thermal label via GET. Pass the same label object as a URL-encoded JSON string in query. Inside that JSON, text items use content…
label_compile	POST /v1/label/compile	Compile a label to printer commands (tsc, zpl, epl, …). POST width, language, and elements. Text uses content and size (1-10), not text or…
label_convert	POST /v1/label/convert	Convert printer commands from one language to another. POST source, from, and to. from is the source language (tsc, zpl, epl, …). to is the…
label_parse	POST /v1/label/parse	Parse printer commands into structured elements. POST source and language (tsc, zpl, epl, …).
label_render	GET /v1/label/render/{id}	Render a previously saved label by ID. Public, no API key required. Supports ?format= override.
label_validate	POST /v1/label/validate	Validate printer commands. POST source (the raw commands) and language (tsc, zpl, epl, …).
label_view	GET /v1/label/view/{id}	View a previously saved label as an HTML page. Public, no API key required. Iframe-embeddable with inline SVG rendering.
qrcode	GET / POST /v1/qrcode	Generate a styled QR code via GET. Output: SVG (default) or PNG. Supports dot styles, gradients, custom corners and all QR versions.
stats	GET /v1/stats	Infrastructure health for an engine or endpoint over the last hour. Not scoped to your account or tenant. Enabled per account: HTTP 403 mea…
usage	GET /v1/usage	Return this account's Chartquery usage and credit balance. No body. Requires an API key.

All ChartQuery SDKs

SDK	Package	Install
Node.js	@chartquery/sdk	npm install @chartquery/sdk
Python	chartquery	pip install chartquery
Go	chartquery-go	go get github.com/chartquery/chartquery-go
.NET	ChartQuery	dotnet add package ChartQuery
Ruby	chartquery	gem install chartquery
PHP	chartquery/sdk	composer require chartquery/sdk
Java	chartquery-java	build from source, see its README
CLI	@chartquery/cli	npm install -g @chartquery/cli
MCP server	@chartquery/mcp	npx -y @chartquery/mcp

License

MIT — see LICENSE.