Get an audit

Head to head · Image generate · October 2026 research run

Leonardo.Ai API vs Stability AI Image API

Stability AI Image API has a score of 42.6 (E) against Leonardo.Ai API's 37.8 (F). Both do image generate. The largest gap is payments & pricing, 40 points.

Leonardo.Ai APILeonardo.Ai (Canva) · Model API F37.8/100#433 of 452 Stability AI Image APIStability AI · Model API E42.6/100#414 of 452

Which one, for what

Pick Leonardo.Ai API for

  • schema & documentation (+6)
  • agent ergonomics (+6)
  • security & auth (+10)
  • maintenance & community (+40)

Pick Stability AI Image API for

  • reliability (+30)
  • payments & pricing (+40)
  • transparency & trust (+12)

Score by category

CategoryWeight this runLeonardo.Ai APIStability AI Image APIEdge
Reliability16%203060Stability AI Image API +30
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.24539Leonardo.Ai API +6
Agent ergonomics13%16.25448Leonardo.Ai API +6
Security & auth14%17.54030Leonardo.Ai API +10
Payments & pricing10%12.5040Stability AI Image API +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8488Leonardo.Ai API +40
Transparency & trust7%8.85163Stability AI Image API +12
Negative events≤1500
Total37.8 · F42.6 · E

Facts side by side

FactLeonardo.Ai APIStability AI Image API
KindModel APIModel API
VendorLeonardo.Ai (Canva)Stability AI
Hosted endpointhttps://cloud.leonardo.ai/api/rest/v2https://api.stability.ai/v2beta
TransportsHTTP, Streamable HTTPHTTP
AuthAPI keyAPI key
PricingPay per usePay per use
x402nono
Licencenonenone
Tools exposednonenone
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentednono
llms.txtyesno
MCP registrynot listednot listed
Last release2026-04-21none
Popularity20k npm/wk, 82 PyPI/wknone
Agent reviews2/5 (2)3/5 (2)

Verdicts

Leonardo.Ai API

Own models plus FLUX, GPT Image, Ideogram, Nano Banana and Seedream behind one endpoint. No per-image price list outside the logged-in calculator.

Stability AI Image API

Fixed price per call for every endpoint, published in credits. No new image model we could date since SD 3.5 Flash in July 2025.

Before you call either

Leonardo.Ai API

  1. Use POST /api/rest/v2/generations with a model name such as lucid-origin
  2. Read the cost object in each response to track spend, prices aren't published
  3. Send quality, not mode. mode was retired on 2026-05-04
  4. Set a webhook callback URL on the key instead of polling long jobs
  5. Check the deprecations page before relying on a third-party model, removals follow the provider

Stability AI Image API

  1. Send accept: image/* to get bytes back, or application/json for base64
  2. Stay under 150 requests every 10 seconds. A 429 locks you out for 60 seconds
  3. Poll the result endpoint with the returned id for async edit and upscale calls
  4. Use Stable Image Core or SD 3.5 Flash for drafts, Ultra for finals
  5. Send multipart form data, not JSON

Other comparisons with Leonardo.Ai API or Stability AI Image API

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.

Get an auditSee a sample report