GPT-5.6 Sol is 50% off on Vercel AI Gateway and OpenRouter — OpenAI's list price did not move

Vercel cut GPT-5.6 Sol to $2.50 / $15 on AI Gateway from August 17 through September 18, 2026. OpenRouter's OpenAI provider shows the same $2.50 / $15. OpenAI's own docs, checked August 18, still list $5 / $30. BYOK and Azure routes stay at list.

Vercel published a changelog on August 17, 2026: GPT-5.6 Sol is 50% off on AI Gateway through September 18. The discounted default rate is $2.50 input / $15.00 output per million tokens. Flex is $1.25 / $7.50. Priority (fast mode) is $5.00 / $30.00. The model ID does not change. BYOK is excluded. (Source: Vercel Changelog, 2026-08-17)

This is not an OpenAI price cut. OpenAI’s GPT-5.6 Sol docs, retrieved August 18, 2026, still list $5 input / $0.50 cached / $30 output. That is the same list price we recorded in the July 30 Luna/Terra cut.

Key facts:

Vercel window: August 17 through September 18, 2026. The discount covers cached tokens, cache writes, long-context requests, every region, and every service tier, including fast mode.
It only applies to requests billed through AI Gateway on the OpenAI provider. BYOK bills at whatever rate you have with your own key.
The model ID stays openai/gpt-5.6-sol. Existing callers pick up the lower rate with no code change. Vercel also says vercel ai-gateway coding-agents setup will apply the discount inside Claude Code, Codex, OpenCode, or Pi.
OpenRouter’s OpenAI provider shows the same $2.50 / $15 (cache read $0.25) as of August 18. Azure on OpenRouter is still $5 / $30. Azure US/EU and Bedrock list $5.50 / $33. OpenRouter does not print an end date on that card.
OpenAI list price is unchanged at $5 / $30. Direct api.openai.com callers do not get this promo.

Vercel changelog pricing table: Default $2.50/$15.00 vs $5.00/$30.00; Flex $1.25/$7.50 vs $2.50/$15.00; Priority fast mode $5.00/$30.00 vs $10.00/$60.00. Dated 17 Aug 2026. — Official Vercel table, retrieved 2026-08-18. Fast mode is half of $10/$60, not half of the list $5/$30. (Source: Vercel Changelog)

What this means if you’re building with GPT-5.6 Sol

1. Route the planner, not the whole stack. The GPT-5.6 switch guide still treats Sol as the planner and Luna as the executor. For this window, a Sol-planner call through AI Gateway or OpenRouter’s OpenAI provider is $2.50 / $15 — old list Terra. Luna on OpenAI is still $0.20 / $1.20 after the July 30 cut.

2. Check the provider, not the model id. On OpenRouter, only the row labeled OpenAI · 50% off is $2.50 / $15. Azure is $5 / $30. Azure US/EU and Bedrock are $5.50 / $33. If your router is set to cheapest-or-balanced and the OpenAI row is saturated, you can silently pay list. Pin the OpenAI provider, or pin Vercel AI Gateway, for the window.

OpenRouter GPT-5.6 Sol page showing $2.50/$15 with a 50% off badge, and a provider table where only the OpenAI row is discounted. Azure remains $5.00/$30.00. Azure US and Azure EU remain $5.50/$33.00. — OpenRouter, retrieved 2026-08-18. The 50% badge is the OpenAI provider. Azure is still list. (Source: openrouter.ai/openai/gpt-5.6-sol)

3. BYOK users get nothing. Vercel says this in the first paragraph. If you pointed AI Gateway at your own OpenAI key to keep spend on an existing invoice, you are still on $5 / $30. Flip off BYOK for Sol during the window, or send Sol through OpenRouter’s OpenAI provider.

4. Do not rewrite budgets as if OpenAI cut Sol. We already published that Luna fell 80% and Terra 20% on July 30, and Sol did not move. That is still true on OpenAI’s docs today. Treat this as a reseller promo with a printed end date on Vercel and no printed end date on OpenRouter.

OpenAI Developers model page for GPT-5.6 Sol showing PRICE $5 · $30 and a text-token table of Input $5.00, Cached input $0.50, Output $30.00, retrieved August 18, 2026. — OpenAI's own card on 2026-08-18. List price did not follow the gateways. (Source: OpenAI model docs)

5. Fast mode is easy to misread. Discounted Priority is $5 / $30 — standard list Sol, not Luna prices. You are paying half of the 2× speed tier, not half of list Sol.

Sources: Vercel Changelog, 2026-08-17 · OpenAI GPT-5.6 Sol docs (retrieved 2026-08-18) · OpenRouter openai/gpt-5.6-sol (retrieved 2026-08-18) · OpenRouter discounted-models collection