ModelRefs / o4 Mini - AI model implementation reference

o4 Mini - AI model implementation reference

o4 Mini is a retired OpenAI reasoning model, built for workloads needing deliberate reasoning at a different latency and cost profile from o3. OpenAI's deprecations page gave both the o4-mini-2025-04-16 snapshot and the o4-mini alias a shutdown date of 23 October 2026, with gpt-5.6-terra as the substitute, so any remaining integration needs migrating rather than tuning. Its suitability was always dependent on task structure, reasoning settings and the quality threshold measured on representative cases.

Overview

o4 Mini is attributed to OpenAI in ModelRefs' canonical registry. Tracked modalities: Text, Image input where supported. Primary use cases considered on ModelRefs: Reasoning-heavy classification, analysis, and coding; High-volume tasks that can validate a smaller reasoning model.

This ModelRefs profile is decision-support material, not a final or universal ranking. Confirm current behavior, access, pricing, limits, licensing, and lifecycle in OpenAI's own documentation, and evaluate o4 Mini on representative workloads before implementation.

Lifecycle

Retired. No longer served. Requests to it fail rather than falling back.

Stopped serving: 23 October 2026
Provider's replacement: gpt-5.6-terra

Provider-documented snapshots

o4-mini-2025-04-16

OpenAI listed the bare o4-mini alias alongside the dated snapshot here, unlike the GPT-4o rows, so the alias stopped resolving on the same date. The fine-tuned ft-o4-mini-2025-04-16 snapshot carried the same shutdown date and substitute. Re-read on the shutdown date itself: the deprecations page still lists both rows with 23 October 2026 and gpt-5.6-terra.

Source: developers.openai.com, checked 2026-10-23.

Benchmark & Evaluation

ModelRefs currently has partial, narrow benchmark coverage for o4 Mini. Treat the available benchmark evidence as one input to the decision, not a guarantee that o4 Mini is the strongest option for your workload, and evaluate it on representative workloads before selecting it.

Provider-reported benchmark results should be interpreted with methodology, dataset, prompting, tool, sampling, and recency limitations in mind.
G.18 registers OpenAI's unqualified simple-evals GPQA row for the o4-mini alias. The separately labeled high- and low-reasoning rows remain outside this canonical claim, and eligibility stays Partial.

Implementation considerations

Compare o4 Mini with both o3 and non-reasoning alternatives on the same evaluation set.
Test reasoning effort, tool use, response length, latency, and failure escalation.
Migration is the immediate task, not tuning: o4-mini-2025-04-16 stopped serving on 23 October 2026 and gpt-5.6-terra needs its own evaluation rather than an assumed carry-over of reasoning behaviour.
Hosted through supported OpenAI API products.
Deprecated with a shutdown on 23 October 2026 covering both the o4-mini-2025-04-16 snapshot and the bare o4-mini alias, with gpt-5.6-terra named as the substitute; the fine-tuned ft-o4-mini-2025-04-16 snapshot carries the same date.

Risks and limitations

Outputs can be incorrect or unsuitable for the intended task; use task-specific evaluation, grounding, and human review where consequences are material.
API availability, model aliases, rate limits, data controls, regions, and prices are mutable and differ by product channel.

Source coverage

ModelRefs reviewed OpenAI's published material on 2026-06-29. Model behavior, access, pricing, limits, and lifecycle can change, so verify the linked provider documentation before implementation. What remains open is recorded on this page: Independent reproduction and broader benchmark coverage remain incomplete. Fit and comparison signals remain provisional until tested on your own workload.

Sources

Continue your research

Use these connected ModelRefs sections to compare alternatives, inspect implementation paths, and review the evidence and governance boundaries relevant to o4 Mini - AI model implementation reference.