Ideogram's API at https://api.ideogram.ai generates images with Ideogram 3.0, which is known for rendering legible text. Requests are multipart form fields (curl's -F; in PostTaco, the Body tab's Form mode).
Create a key in Ideogram's API settings and send it as the Api-Key header. In the examples it's written {{IDEOGRAM_API_KEY}}. Remix and edit endpoints need an image upload, which PostTaco doesn't support yet.
Full reference: https://developer.ideogram.ai/api-reference/api-reference/generate-v3
rendering_speed: TURBO, DEFAULT, or QUALITY. The response's data[].url links to the image.
curl -X POST https://api.ideogram.ai/v1/ideogram-v3/generate \
-H "Api-Key: {{IDEOGRAM_API_KEY}}" \
-F prompt="a neon sign that says POSTTACO" \
-F rendering_speed=TURBO \
-F aspect_ratio=1x1