The quick brown fox jumps over the lazy dog
OpenAI Sans vs Söhne
Two proprietary sans-serifs that both lean neutral, but they come from opposite directions. OpenAI Sans is a 2025 bespoke brand face that pairs geometric structure with rounder, deliberately imperfect forms, while Söhne is Klim Type Foundry's 2019 grotesque built on the memory of Akzidenz-Grotesk as seen on New York Subway signage.
OpenAI Sans is a commercial font, so it is shown here in Inter, its closest free alternative. All free alternatives to OpenAI Sans → Söhne is a commercial font, so it is shown here in Inter, its closest free alternative. All free alternatives to Söhne →
The quick brown fox jumps over the lazy dog
- Söhne was drawn by Kris Sowersby from Akzidenz-Grotesk's Halbfett weight, so its proportions are set by the semibold and the family is built outward from there rather than from the regular.
- OpenAI Sans was developed by OpenAI's in-house design team with Berlin foundry ABC Dinamo, blending geometric precision with softer, more approachable shapes and subtle irregularities meant to feel less robotic.
- Söhne is the larger system: eight weights from Extraleicht to Extrafett with italics, plus Schmal, Breit and Mono companions, while OpenAI's guidelines describe five core weights with matching italics.
- OpenAI Sans is custom and not licensed to the public, whereas Söhne is a commercial retail font sold by Klim under separate one-off desktop, web and app licences, so licensing cost is a real factor only on the Söhne side.
OpenAI Sans
Reach for OpenAI Sans only as a reference: it belongs to OpenAI alone, so if you want its rounded, friendly, geometric-leaning feel you will need a free alternative rather than the font itself.
Söhne
Reach for Söhne when you want a disciplined, Akzidenz-flavoured grotesque with a deep weight range and matching condensed, wide and mono families, and your budget covers Klim's licensing.