GPT-5.6 Sol, Terra & Luna Now on APIMaster — 90% Off Launch Offer

What OpenAI Announced

OpenAI is introducing a new naming scheme with GPT-5.6:

• The number (5.6) marks the generation.
• Sol, Terra, and Luna are durable capability tiers that can evolve on their own release cadence.

During the preview, all three models are aimed at different cost/latency points on the same generation:

Tier	Positioning	Input (per 1M tokens)	Cached input	Output (per 1M tokens)
Sol	Flagship for ambitious agentic work	$5.00	$0.50	$30.00
Terra	Balanced model for everyday work	$2.50	$0.25	$15.00
Luna	Fast, affordable high-volume work	$1.00	$0.10	$6.00

OpenAI states that Terra matches GPT-5.5-level performance at roughly half the cost, while Luna delivers strong capability at the lowest price point in the family.

Sol: Flagship Capabilities Developers Care About

GPT-5.6 Sol is positioned as OpenAI’s strongest model yet for long-horizon, tool-using workflows.

Highlights from the announcement:

• Terminal-Bench 2.1 — new state of the art on command-line agent tasks (planning, iteration, multi-tool coordination).
• GeneBench v1 — improved biology/genomics analysis vs GPT-5.5 with fewer tokens.
• Cybersecurity — competitive on ExploitBench² and ExploitGym³ with strong efficiency; OpenAI emphasizes defensive use cases (patching, review, education) over offensive automation.
• max reasoning effort — gives Sol more time to reason deeply on hard problems.
• ultra mode — coordinates subagents for complex work beyond a single agent loop.

For production coding stacks (Codex, Cursor, custom agents), Sol is the tier to watch when your bottleneck is quality and multi-step reliability, not raw tokens per second.

Terra and Luna: When to Pick Which Tier

Use this decision frame:

If your workload is…	Start with…	Why
Multi-file refactors, long agent runs, security research, deep reasoning	Sol	Highest capability ceiling; new max / ultra modes
Daily chat, RAG, moderate coding, most SaaS features	Terra	~GPT-5.5 class at 2× lower official price vs Sol
Classification, extraction, high-QPS chat, bulk summarization	Luna	Lowest $/token; best for volume

Rule of thumb: Luna for throughput, Terra for default production, Sol for hard agentic tasks where failure cost exceeds token cost.

Pricing Details That Change Your Bill

Beyond the headline $/1M rates, GPT-5.6 introduces more predictable prompt caching:

• Explicit cache breakpoints in the API.
• Minimum cache lifetime: 30 minutes on GPT-5.6 and later models.
• Cache writes billed at 1.25× uncached input rate.
• Cache reads keep the familiar 90% discount on cached input.

For agent loops that reuse system prompts, tool schemas, or long context prefixes, Terra and Luna can look much cheaper in practice than headline input pricing — but only if your integration actually hits the cache.

Example: on Sol, uncached input is $5/M; cached input is $0.50/M — a 10× reduction on repeated prefix tokens.

Availability: GPT-5.6 Is Live Now

GPT-5.6 is generally available across ChatGPT, Codex, and the OpenAI API. APIMaster has also launched all three API routes: gpt-5.6-sol, gpt-5.6-terra, and gpt-5.6-luna.

For developers, that means no application rewrite: create an APIMaster key, keep the OpenAI SDK, change the base URL, and select the model. You can also switch between tiers without changing your message format.

Safety Stack: Why You May See Refusals or Delays

GPT-5.6 ships with OpenAI’s most layered safety stack to date, especially around cyber and biology dual-use requests.

Expect during preview:

• Hard refusals on prohibited cyber assistance, including jailbreak attempts.
• Paused generations when classifiers flag high-risk output for secondary review.
• Account-level review when patterns look like persistent misuse vs legitimate security work.
• Occasional false positives on legitimate code review, CTF prep, or defensive testing.

OpenAI reports 700k+ A100-equivalent GPU hours of automated red-teaming plus ongoing human expert testing. For enterprise buyers, they mention future privacy-preserving detection and customer-operated safety controls.

If you operate an AI gateway or resell model access, factor higher tail latency and non-deterministic blocks into SLAs during the preview window.

GPT-5.6 vs GPT-5.5: What Actually Changed

Dimension	GPT-5.5 (prior gen)	GPT-5.6 family
Tier naming	Single generation label	Sol / Terra / Luna tiers within 5.6
Cost structure	Prior list pricing	Terra ~half Sol; Luna lowest
Agent modes	Standard reasoning efforts	Sol adds max + ultra subagents
Caching	Prior behavior	30-min min cache, explicit breakpoints, 1.25× write premium
Cyber evals	Strong	Sol/Terra/Luna all improve; Sol most capable
Release	GA paths	Phased preview with stronger safeguards

GPT-5.6 Is 90% Off on APIMaster.ai

All three GPT-5.6 models are available now on APIMaster.ai with a limited-time 90% OFF offer. Access is pay-as-you-go from $1, requires no subscription, and works with the OpenAI SDK.

Step-by-step

1. Register — free account, email or OAuth.
2. Top up from $1 — wallet in the console; supports PayPal, card, and other methods listed at checkout (often easier than binding a card directly on platform.openai.com).
3. Open the marketplace — search for GPT-5.6, Sol, Terra, or Luna, then choose a 90%-off route and review its live price.
4. Create an API key in the console → copy once.
5. Point your SDK at APIMaster’s base URL and the model slug shown on the marketplace card:

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_APIMASTER_KEY",
    base_url="https://apimaster.ai/v1",
)

resp = client.chat.completions.create(
    model="gpt-5.6-terra",  # or gpt-5.6-sol / gpt-5.6-luna
    messages=[{"role": "user", "content": "Reply with exactly: ok"}],
    max_tokens=16,
)
print(resp.choices[0].message.content)

6. Verify before you scale — run the same key through the free model fingerprint tester. During preview scarcity, some relays silently downgrade model tier; APIMaster’s detection helps you confirm you’re getting what you paid for.

Tier picking on APIMaster: use Luna routes for bulk/low-risk calls, Terra as your default production model, and Sol when agent quality matters more than $/token.

Get GPT-5.6 at 90% off → The promotional price may change, so check the live marketplace rate before sending production traffic.

Start Building with GPT-5.6 Today

Sol, Terra, and Luna are already on APIMaster. Follow these channels for price changes, route updates, and model verification results:

• Telegram group — model launch alerts, pricing changes, and support (t.me/apimasterai, ~community channel)
• Contact / community page — Telegram QR and feedback form
• Blog — deep dives like this one when major models ship
• Changelog — product and routing updates

APIMaster publishes model availability and verification updates so you can switch base_url without rewriting your app.

Create your account → · Browse marketplace → · Join Telegram →

FAQ

What are GPT-5.6 Sol, Terra, and Luna? They are three capability tiers in OpenAI’s GPT-5.6 generation: Sol is the flagship agentic model, Terra is a balanced everyday tier (~GPT-5.5 class at lower cost), and Luna is the fast, lowest-cost tier for high-volume work.

How much does GPT-5.6 cost on the official API? List pricing per 1M tokens is Sol $5 input / $30 output, Terra $2.50 / $15, Luna $1 / $6, with cached input at 10% of uncached input price (90% discount). Cache writes cost 1.25× uncached input; cache entries last at least 30 minutes.

Is GPT-5.6 available on APIMaster today? Yes. GPT-5.6 Sol, Terra, and Luna are all live on APIMaster.ai and currently participate in the 90% OFF launch promotion.

What is GPT-5.6 Sol ultra mode? ultra goes beyond a single agent by orchestrating subagents to accelerate complex tasks. It targets workloads where parallel exploration beats one long serial chain.

How does GPT-5.6 compare to GPT-5.5 for developers? Terra is positioned as competitive with GPT-5.5 at about half the official cost. Sol exceeds GPT-5.5 on agentic, biology, and cyber benchmarks OpenAI published. Luna trades peak capability for lowest $/token.

How do I choose between Sol, Terra, and Luna? Choose Sol for the highest capability and demanding agents, Terra as the balanced production default, and Luna for low-latency, high-volume workloads.

Where can I read the primary source? OpenAI’s announcement: GPT-5.6: Frontier intelligence that scales with your ambition (July 9, 2026).

Sources & further reading

• OpenAI — GPT-5.6: Frontier intelligence that scales with your ambition (primary announcement, July 9, 2026)
• APIMaster marketplace — live model pricing
• APIMaster — free API model fingerprint tester
• How to verify your OpenAI API is serving the real model