GPT-4o Mini (07-18) vs GPT-5.3-Codex
GPT-4o Mini (07-18) (2024) and GPT-5.3-Codex (2026) are agentic coding models from OpenAI. GPT-4o Mini (07-18) ships a 128K-token context window, while GPT-5.3-Codex ships a 400K-token context window. On pricing, GPT-4o Mini (07-18) costs $0.15/1M input tokens versus $1.75/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
GPT-4o Mini (07-18) is ~1067% cheaper at $0.15/1M; pay for GPT-5.3-Codex only for coding workflow support.
Decision scorecard
Local evidence first| Signal | GPT-4o Mini (07-18) | GPT-5.3-Codex |
|---|---|---|
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 128K | 400K |
| Cheapest output | $0.6/1M tokens | $14/1M tokens |
| Provider routes | 3 tracked | 2 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- GPT-4o Mini (07-18) has the lower cheapest tracked output price at $0.6/1M tokens.
- GPT-4o Mini (07-18) has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags GPT-4o Mini (07-18) for Coding, RAG, and Agents.
- GPT-5.3-Codex has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.3-Codex uniquely exposes Reasoning, Function calling, and Tool use in local model data.
- Local decision data tags GPT-5.3-Codex for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
GPT-4o Mini (07-18)
$270
Cheapest tracked route: OpenAI API
GPT-5.3-Codex
$4,900
Cheapest tracked route: OpenRouter
Estimated monthly gap: $4,630. Batch, cache, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter and OpenAI API; start route-level A/B tests there.
- GPT-5.3-Codex is $13.40/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- GPT-5.3-Codex adds Reasoning, Function calling, and Tool use in local capability data.
- Provider overlap exists on OpenAI API and OpenRouter; start route-level A/B tests there.
- GPT-4o Mini (07-18) is $13.40/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning, Function calling, and Tool use before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2024-07-18 | 2026-02-05 |
| Context window | 128K | 400K |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2023-10 | 2025-08 |
Pricing and availability
| Pricing attribute | GPT-4o Mini (07-18) | GPT-5.3-Codex |
|---|---|---|
| Input price | $0.15/1M tokens | $1.75/1M tokens |
| Output price | $0.6/1M tokens | $14/1M tokens |
| Providers |
Capabilities
| Capability | GPT-4o Mini (07-18) | GPT-5.3-Codex |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | No | No |
| Reasoning | No | Yes |
| Function calling | No | Yes |
| Tool use | No | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on reasoning mode: GPT-5.3-Codex, function calling: GPT-5.3-Codex, and tool use: GPT-5.3-Codex. Both models share vision, structured outputs, and code execution, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, GPT-4o Mini (07-18) lists $0.15/1M input and $0.6/1M output tokens, while GPT-5.3-Codex lists $1.75/1M input and $14/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts GPT-4o Mini (07-18) lower by about $5.14 per million blended tokens. Availability is 3 providers versus 2, so concentration risk also matters.
Choose GPT-4o Mini (07-18) when coding workflow support, lower input-token cost, and broader provider choice are central to the workload. Choose GPT-5.3-Codex when coding workflow support and larger context windows are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Which has a larger context window, GPT-4o Mini (07-18) or GPT-5.3-Codex?
GPT-5.3-Codex supports 400K tokens, while GPT-4o Mini (07-18) supports 128K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, GPT-4o Mini (07-18) or GPT-5.3-Codex?
GPT-4o Mini (07-18) is cheaper on tracked token pricing. GPT-4o Mini (07-18) costs $0.15/1M input and $0.6/1M output tokens. GPT-5.3-Codex costs $1.75/1M input and $14/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is GPT-4o Mini (07-18) or GPT-5.3-Codex open source?
GPT-4o Mini (07-18) is listed under Proprietary. GPT-5.3-Codex is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, GPT-4o Mini (07-18) or GPT-5.3-Codex?
Both GPT-4o Mini (07-18) and GPT-5.3-Codex expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for reasoning mode, GPT-4o Mini (07-18) or GPT-5.3-Codex?
GPT-5.3-Codex has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run GPT-4o Mini (07-18) and GPT-5.3-Codex?
GPT-4o Mini (07-18) is available on OpenAI API, OpenRouter, and Replicate API. GPT-5.3-Codex is available on OpenRouter and OpenAI API. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-11. Data sourced from public model cards and provider documentation.