GPT-5.2 Codex vs GPT-5.5 Instant
GPT-5.2 Codex (2025) and GPT-5.5 Instant (2026) compare a coding-specialized model against a standalone API model. GPT-5.2 Codex ships a not-yet-sourced context window, while GPT-5.5 Instant ships a 400k-token context window. On pricing, GPT-5.2 Codex costs $1.75/1M input tokens versus $5/1M for the alternative. This page treats the result as workflow and deployment fit, not a universal model winner.
Treat this as a product-type comparison: GPT-5.2 Codex is coding-specialized model, while GPT-5.5 Instant is standalone API model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | GPT-5.2 Codex | GPT-5.5 Instant |
|---|---|---|
| Product type | Coding-specialized model | Standalone API model |
| Best for | custom coding agents, code generation, and tool loops | multimodal apps and tool-calling agents |
| Decision fit | Coding, Agents, and Vision | Coding, RAG, and Agents |
| Context window | — | 400k |
| Cheapest output | $14/1M tokens | $30/1M tokens |
| Provider routes | 1 tracked | 1 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- GPT-5.2 Codex has the lower cheapest tracked output price at $14/1M tokens.
- GPT-5.2 Codex uniquely exposes Reasoning in local model data.
- Local decision data tags GPT-5.2 Codex for Coding, Agents, and Vision.
- GPT-5.5 Instant has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.5 Instant uniquely exposes Structured outputs in local model data.
- Local decision data tags GPT-5.5 Instant for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
GPT-5.2 Codex
$4,900
Cheapest tracked route/tier: Vercel AI Gateway
GPT-5.5 Instant
$11,500
Cheapest tracked route/tier: OpenAI API
Estimated monthly gap: $6,600. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for GPT-5.2 Codex and GPT-5.5 Instant; plan for SDK, billing, or endpoint changes.
- GPT-5.5 Instant is $16/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Reasoning before moving production traffic.
- GPT-5.5 Instant adds Structured outputs in local capability data.
- No overlapping tracked provider route is sourced for GPT-5.5 Instant and GPT-5.2 Codex; plan for SDK, billing, or endpoint changes.
- GPT-5.2 Codex is $16/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Structured outputs before moving production traffic.
- GPT-5.2 Codex adds Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-12-18 | 2026-05-05 |
| Context window | — | 400k |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-08 | 2025-08 |
Pricing and availability
| Pricing attribute | GPT-5.2 Codex | GPT-5.5 Instant |
|---|---|---|
| Input price | $1.75/1M tokens | $5/1M tokens |
| Output price | $14/1M tokens | $30/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.2 Codex | GPT-5.5 Instant |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | No | Yes |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on reasoning mode: GPT-5.2 Codex and structured outputs: GPT-5.5 Instant. Both models share vision, multimodal input, function calling, and tool use, 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-5.2 Codex lists $1.75/1M input and $14/1M output tokens on the cheapest tracked provider, while GPT-5.5 Instant lists $5/1M input and $30/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts GPT-5.2 Codex lower by about $7.08 per million blended tokens. Availability is 1 providers versus 1, so concentration risk also matters.
Choose GPT-5.2 Codex when coding workflow support and lower input-token cost are central to the workload. Choose GPT-5.5 Instant when coding workflow support 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 is cheaper, GPT-5.2 Codex or GPT-5.5 Instant?
GPT-5.2 Codex is cheaper on tracked token pricing. GPT-5.2 Codex costs $1.75/1M input and $14/1M output tokens. GPT-5.5 Instant costs $5/1M input and $30/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is GPT-5.2 Codex or GPT-5.5 Instant open source?
GPT-5.2 Codex is listed under Proprietary. GPT-5.5 Instant 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-5.2 Codex or GPT-5.5 Instant?
Both GPT-5.2 Codex and GPT-5.5 Instant 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 multimodal input, GPT-5.2 Codex or GPT-5.5 Instant?
Both GPT-5.2 Codex and GPT-5.5 Instant expose multimodal input. 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-5.2 Codex or GPT-5.5 Instant?
GPT-5.2 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-5.2 Codex and GPT-5.5 Instant?
GPT-5.2 Codex is available on Vercel AI Gateway. GPT-5.5 Instant is available on OpenAI API. Provider coverage can affect latency, region availability, compliance posture, and fallback options. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Continue comparing
Last reviewed: 2026-05-22. Data sourced from public model cards and provider documentation.