OpenAI API vs Inngest
Frontier models: GPT-5, o-series reasoning, image, audio, embeddings
vs. Durable functions + event-driven workflows for modern apps
Pricing tiers
OpenAI API
Free Tier (Trial)
$5 free credit for new accounts. Rate-limited.
Free
Pay-as-you-go
No monthly min. Per-token pricing by model.
$0 base (usage-based)
Usage Tiers (1-5)
Automatic tier promotion based on cumulative spend. Higher tiers = higher rate limits + new model access.
$0 base (usage-based)
Enterprise
Custom. Priority access, SLA, dedicated capacity.
Custom
Inngest
Free
$0. 50K steps/mo + 1K concurrent executions. 7-day log retention. 1 environment.
Free
OSS (self-host)
Free forever. Inngest Dev Server + self-hosted Inngest runtime. Apache 2.0.
$0 base (usage-based)
Starter
$20/mo. 250K steps/mo. 5K concurrency. 14-day retention. 3 envs.
$20/mo
Pro
$75/mo. 1M steps/mo. 10K concurrency. 30-day retention. Priority support.
$75/mo
Enterprise
Custom. SSO, HIPAA, dedicated clusters, self-host with Inngest Enterprise.
Custom
Free-tier quotas head-to-head
Comparing free-tier on OpenAI API vs free on Inngest.
| Metric | OpenAI API | Inngest |
|---|---|---|
| No overlapping quota metrics for these tiers. | ||
Features
OpenAI API · 12 features
- Assistants API — Stateful assistants with tools, threads, file search.
- Batch API — 50% discount for async processing within 24h.
- Chat Completions API — Classic /v1/chat/completions endpoint.
- Files API — Upload docs for retrieval, fine-tuning, batch.
- Fine-Tuning — Supervised + DPO fine-tuning for GPT-4o, GPT-4.1, GPT-4o-mini.
- Function Calling — JSON-schema tool calling; parallel calls supported.
- Moderation — Safety classifier API (free).
- Prompt Caching — Auto-cache repeated prefixes; 50% cheaper cached hits.
- Realtime API — WebSocket streaming voice + text with low latency.
- Responses API — Stateful conversational API.
- Structured Outputs — Enforced JSON schema compliance.
- Vision — Image input for GPT models.
Inngest · 14 features
- AgentKit — Build AI agents as durable Inngest functions.
- Auto Retries — Configurable retries with exponential backoff.
- Concurrency Controls — Per-function and per-user concurrency limits.
- Cron Triggers — Scheduled functions via cron syntax.
- Debounce — Coalesce rapid-fire events into one execution.
- Dev Server — Local Inngest runtime for dev.
- Durable Steps — step.run, step.sleep, step.waitForEvent.
- Event System — Typed events with schemas.
- Fan Out / Batching — Process many events in parallel with batch control.
- Priority Lanes — Route premium customers to faster execution.
- Rate Limiting — Throttle events per key.
- Realtime — Stream function output to clients.
- Replay — Re-run past functions with new code.
- Self-Host — OSS runtime — run your own Inngest.
Developer interfaces
| Kind | OpenAI API | Inngest |
|---|---|---|
| CLI | — | inngest-cli (dev server) |
| SDK | openai-dotnet, openai-go, openai-node, openai-python | inngestgo, inngest (Python), inngest (TS/Node) |
| REST | OpenAI REST API | Inngest REST API |
| MCP | OpenAI MCP | Inngest MCP |
| OTHER | Realtime API (WebSocket) | Inngest Cloud Dashboard |
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