OpenAI API: pricing, limits, errors and comparisons

o3 is $2/$8 per 1M tokens and o3-pro $20/$80, but OpenAI removes both on December 11, 2026 (o3-mini on October 23). Prices, dates, and migration math.

Updated Sep 30, 2026

GPT-4o pricing is $2.50 per million input tokens and $10.00 per million output tokens. Learn the complete cost structure including cached inputs, batch API discounts, and how to calculate your real-world API expenses with practical examples.

Updated Jan 16, 2026

Every documented OpenAI image generation limit as of October 9, 2026: per-tier IPM and TPM, model limitations, moderation blocks, size rules, status, availability.

Updated Oct 9, 2026

The OpenAI API 'quota exceeded' error (HTTP 429) comes in two distinct types: insufficient_quota (billing issue) and rate_limit_exceeded (too many requests). This guide helps you diagnose which type you have and provides step-by-step solutions for each, including what to do when you have credits but still get the error.

Updated Oct 5, 2026

OpenAI API free trial credits were discontinued in mid-2025. This guide explains your real options: the extremely limited free tier, the $5 minimum investment path, and genuinely free alternatives like Google Gemini that actually work.

Updated Feb 2, 2026

Complete guide to free OpenAI API access in 2026. Covers official free tier (3 RPM), API proxy services like Puter.js, OpenRouter alternatives, and 15+ provider comparison with cost optimization strategies.

Updated Jan 20, 2026

Learn proven methods to access OpenAI's revolutionary o1 reasoning models for free or at 90% reduced cost through API gateways

Updated Jan 28, 2025

Understand the risks of searching for free OpenAI API keys on GitHub and discover legitimate, affordable alternatives like LaoZhang.ai that provide safe, legal access to AI capabilities.

Updated Jan 16, 2025

Learn how to access OpenAI's API for free in 2025, explore alternative free AI providers, and discover cost-effective strategies including open-source models and affordable gateways.

Updated Jan 16, 2025

Complete guide to fixing GPT-5.2 reasoning timeout errors. Covers timeout configuration, reasoning effort optimization, background processing implementation, and production-ready Python code examples.

Updated Oct 5, 2026

The 'Failed to load subscription for selected organization' error on OpenAI prevents access to billing, playground, and API features. This comprehensive guide provides 5-step diagnosis, solutions verified by OpenAI Community, organization management fixes, and billing troubleshooting based on 2025 user reports.

Updated Oct 5, 2026

Gemini isn't cheapest everywhere: Luna and Haiku 5.5 tie 2.5 Flash-Lite (past 2.5 users only) on input and beat 3.1 Flash-Lite; Sol and Sonnet 5.5 beat 3.1 Pro.

Updated Oct 14, 2026

Any API account can now run GPT-6.1 Sol on Ultrafast at a fifth of Astra Ultrafast's input/output rates. Codex and Work need Pro $500 or eligible Enterprise/Edu.

Updated Oct 10, 2026

Use GPT-6.1 Sol for test-checked volume work, Opus 5.5 where review costs more than tokens. Sol Ultrafast is open to any API account; Opus Fast mode is waitlisted.

Updated Oct 10, 2026

Identical bills up to 100,000-token prompts; above that, Luna is 5x cheaper per request until 272K. Below the line, compare cost per task at matched quality.

Updated Oct 8, 2026

Gemini API is generally 20-50% cheaper than OpenAI for equivalent model tiers. This comprehensive guide compares Gemini 2.5 Pro ($1.25/1M input) vs GPT-4o ($2.50/1M input), explores real-world cost scenarios, and helps you decide which provider offers better value for your specific use case.

Updated Oct 5, 2026

Opus 5.5 costs less above 272K input tokens and on cache reads; GPT-5.6 Sol writes about half the output per task. Already on Sol? Test GPT-6 Sol or the newer GPT-6.1 Sol first.

Updated Oct 1, 2026

Start new work and any tools-plus-reasoning flow on Responses. Keep Chat Completions for working text flows, n > 1, or providers that only speak Chat Completions.

Updated Sep 25, 2026

Luna's listed token rates are one-twentieth of Sol's in matched API tiers. Here is the math for an actual request and the separate Codex credit comparison.

Updated Sep 23, 2026

Their standard input and output rates match. Cache behavior, Astra's 272K threshold, batch processing, tools, and your token mix determine the actual bill.

Updated Sep 5, 2026

GPT-5.4 nano is usually the better cheap OpenAI API model for new workloads because it costs less than GPT-5 mini, has a newer cutoff, and wins most official March 2026 coding and tool benchmarks. GPT-5 mini still survives in a narrow legacy niche.

Updated Mar 22, 2026

For most new OpenAI API builds, GPT-5.4 mini is the better pick than GPT-5.2 because it is much cheaper, faster, and positioned for high-volume agent workflows. GPT-5.2 mostly remains useful as a migration baseline or legacy validation path.

Updated Mar 22, 2026

GPT-5 nano is still the cheapest OpenAI model in this comparison, but GPT-5.4 nano is usually the better current cheap default for new workloads because it keeps the same context and rate limits while adding a newer cutoff and broader cheap-agent tooling.

Updated Mar 21, 2026

As of March 21, 2026, GPT-5.4 mini is the stronger default for OpenAI-native coding subagents and tool-heavy software workflows, while Gemini 3 Flash is the better pick when you want a cheaper 1M-context multimodal fast lane with Google grounding.

Updated Mar 21, 2026

GPT-5.4 is much more expensive than GPT-5 mini, but it also brings a larger context window, a newer cutoff, and a broader tool surface. This guide explains when the premium is worth paying, when GPT-5 mini is still enough, and when you should test GPT-5.4 mini instead.

Updated Mar 21, 2026

GPT-5.4 is the better choice when you need maximum intelligence and long context, while GPT-5.4 mini is often the smarter production default for cheaper, faster, higher-volume coding and agent workflows.

Updated Mar 21, 2026

GPT-5.4 mini and GPT-5.4 nano share the same context window and knowledge cutoff, but they are not interchangeable. This guide explains when mini's stronger coding and computer-use fit is worth the higher price and when nano should own the cheap high-volume lane.

Updated Mar 21, 2026

GPT-5.4 mini costs more than GPT-5 mini, but OpenAI now recommends it for most new low-latency, high-volume builds. This guide compares price, tool support, benchmarks, and when the cheaper legacy model still makes sense.

Updated Mar 20, 2026

GPT-5.4 is the better default for most developers who want one model for coding, long-context work, and tool-heavy agents in March 2026. Claude Sonnet 4.6 still has a real place in Claude-first workflows, but its base published API pricing is not cheaper than GPT-5.4.

Updated Mar 19, 2026

As of February 2026, three heavyweight AI models launched in the same week: Claude Opus 4.6 ($5/MTok, best reasoning), GPT-5.3 Codex (~$1.75/MTok, fastest terminal tasks), and GLM-5 (~$0.11/MTok, open-source 745B MoE). This guide provides the industry's first complete three-way comparison with verified benchmarks, real-world cost analysis, and a clear decision framework.

Updated Feb 12, 2026

OpenAI API and Azure OpenAI serve different needs: OpenAI offers simpler setup and faster access to new models, while Azure provides enterprise-grade security with VNet support, SLA guarantees, and compliance certifications. This guide helps you make the right choice with code examples, pricing analysis, and a decision framework.

Updated Feb 3, 2026

Comparing OpenAI API with alternatives in 2026? GPT-4o costs $2.50/$10 per million tokens, Claude 3.5 Sonnet offers $3/$15, and Gemini 2.5 Pro provides up to 2M context at $1.25-$2.50. Get complete pricing, features, and migration code.

Updated Feb 2, 2026

A 400-token decision costs $0.00004, or $40 per million. With a long fixed prompt, GPT-6 Luna plus prompt caching can cost about a fifth as much.

Updated Oct 10, 2026

On Plus, Astra runs only in ChatGPT Work and Codex, at an estimated 5–45 messages per five hours. GPT-6.1 Sol gets roughly three times as many.

Updated Oct 10, 2026

Create the key inside a project, copy it the one time it's shown, store it as OPENAI_API_KEY, and buy at least $5 of API credits before your first call.

Updated Sep 30, 2026

Start new workloads on GPT-5.6 Terra, move hard quality-critical tasks to Sol, and test Luna only where constraints and automatic validation make its lower price safe to capture.

Updated Aug 25, 2026

68% of international credit cards get declined when purchasing OpenAI API access. Learn how to successfully buy API credits through 5 proven methods, including the 100% success rate LaoZhang.ai gateway.

Updated Jul 16, 2025