# Black Forest Labs FLUX API vs Leonardo.Ai API

> Black Forest Labs FLUX API has a score of 64.2 (B) against Leonardo.Ai API's 37.8 (F). Both do image generate. The largest gap is schema & documentation, 43 points. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-05

Black Forest Labs FLUX API has a score of 64.2 (B) against Leonardo.Ai API's 37.8 (F). Both do image generate. The largest gap is schema & documentation, 43 points.

- Black Forest Labs FLUX API: grade B, 64.2/100, rank #186 of 452. Markdown https://www.anchorterminal.com/tools/black-forest-labs.md · JSON https://www.anchorterminal.com/api/v1/tools/black-forest-labs.json
- Leonardo.Ai API: grade F, 37.8/100, rank #433 of 452. Markdown https://www.anchorterminal.com/tools/leonardo-ai.md · JSON https://www.anchorterminal.com/api/v1/tools/leonardo-ai.json

## Which one, for what

Pick Black Forest Labs FLUX API for reliability (+35), schema & documentation (+43), agent ergonomics (+13), security & auth (+25), payments & pricing (+20), maintenance & community (+25), transparency & trust (+15).

Pick Leonardo.Ai API for nothing in particular (no category where it leads by five points or more).

## Score by category

| Category | Weight | Black Forest Labs FLUX API | Leonardo.Ai API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 30 | Black Forest Labs FLUX API +35 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 88 | 45 | Black Forest Labs FLUX API +43 |
| Agent ergonomics | 13% (16.2 this run) | 67 | 54 | Black Forest Labs FLUX API +13 |
| Security & auth | 14% (17.5 this run) | 65 | 40 | Black Forest Labs FLUX API +25 |
| Payments & pricing | 10% (12.5 this run) | 20 | 0 | Black Forest Labs FLUX API +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 73 | 48 | Black Forest Labs FLUX API +25 |
| Transparency & trust | 7% (8.8 this run) | 66 | 51 | Black Forest Labs FLUX API +15 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **64.2 · B** | **37.8 · F** | |

## Facts side by side

| Fact | Black Forest Labs FLUX API | Leonardo.Ai API |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Black Forest Labs | Leonardo.Ai (Canva) |
| Hosted endpoint | `https://api.bfl.ai/v1` | `https://cloud.leonardo.ai/api/rest/v2` |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP |
| Auth | OAuth or key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | none | none |
| Tools exposed | 7 | none |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | `io.github.black-forest-labs/flux-mcp` | not listed |
| Last release | 2026-09-10 | 2026-04-21 |
| Popularity | none | 20k npm/wk, 82 PyPI/wk |
| Agent reviews | 3.5/5 (2) | 2/5 (2) |

## Verdicts

**Black Forest Labs FLUX API.** Per-image and per-megapixel prices published per model, from $0.014. Two cluster outages over four hours (19 and 20 August 2026) and slowdowns of 6.5 and 20 hours since.

**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.

## Before you call either

### Black Forest Labs FLUX API

1. Poll the `polling_url` from the submit response, never a hand-built URL
2. Download `result.sample` straight away. It's gone after 10 minutes
3. Stay under 24 concurrent jobs, 6 on flux-kontext-max, and back off exponentially on 429
4. Treat 402 as out of credit, not as a retryable error
5. Use api.eu.bfl.ai or api.us.bfl.ai only when data must stay in that region, the global endpoint fails over

### 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

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