Runway Gen-4: the complete guide

Runway positions Gen-4 as a general-purpose video generator inside an editing product: motion brush, camera controls, inpainting, upscale and stitch flows sit beside raw generation. That matters for agencies — you may pay more per second than fal-only pipelines, but you also skip round-tripping through After Effects for simple fixes.

• ▸Gen-4.5 (latest): highest realism and cinematography in Runway's lineup — 12 credits per second on API.
• ▸Gen-4 Video / Gen-4 Turbo: image-to-video focused; Turbo at 5 credits/s is the budget API path.
• ▸Gen-4 Aleph / Aleph 2.0: video-to-video editing and stylization — different pricing (15–28 credits/s).
• ▸Act-Two: character performance animation from a reference performance clip — 5 credits/s, 3 s minimum.
• ▸Web app subscriptions (Standard $28/mo, Pro $76/mo, etc.) bundle credits separate from Developer API credits.

Developer API: 1 credit = $0.01. Video cost = credits per second × duration × $0.01.

Web app subscriptions amortize differently — a Pro plan at $28/mo with 2,250 credits makes each credit ~$0.0124, so Gen-4 Turbo at 5 credits/s is ~$0.062/s effective before you count unused credits. API pay-as-you-go is simpler for automation: $0.05/s Turbo, $0.12/s Gen-4.5.

• ▸Free tier: 125 one-time credits — enough for short tests, not production battles.
• ▸Unlimited plan ($188/mo): unlimited Gen-3 generations plus a Gen-4 credit pool — read the fine print before assuming unlimited Gen-4.5.
• ▸Upscale to 4K: flat ~50 credits on web app — factor into total deliverable cost.
• ▸No public affiliate program as of July 2026.

Runway Developer API uses task-based async jobs. Model selection happens via the model field on the generation task — exact schema is in the Runway API docs. Typical inputs:

Authentication: API key from the Runway Developer Portal. Poll task status until SUCCEEDED; download output URL. Failed tasks may still consume credits depending on failure code — safety blocks on input are documented as non-refundable in third-party API guides; verify in your dashboard.

• ▸Instagram and vertical ads: Runway's docs emphasize polished motion on fashion, lifestyle and product — start from a strong still for Gen-4 Turbo i2v.
• ▸Image-to-video from listing photos: crop to 9:16 with safe margins; Turbo at $0.25 per 5 s is a common agency workflow.
• ▸Use motion brush and camera controls in the web app when API output is 80% right — the suite value is fixing in-place.
• ▸Gen-4.5 text-to-video: write lighting and lens feel explicitly; Runway markets this tier for "high realism and cinematography".
• ▸Avoid architecture-only prompts without reference images — our villa tests show higher retry rates than on Kling for pure t2v facades.
• ▸Voice: use Runway Characters or external ElevenLabs — do not assume native lip-sync on Gen-4 video gens.

• ▸Wins: client-ready polish on vertical ads, image-to-video from brand stills, in-app fix tools without leaving Runway.
• ▸Loses on raw API cost at volume when retries stack — Kling Standard and Hailuo undercut per attempt.
• ▸Loses to Veo on speech-led UGC with native lip-sync in one pass.
• ▸Loses to Seedance on multi-reference brand campaigns.

Documentation verdict: Runway Gen-4 is the pick when the deliverable must look client-ready with minimal post — especially image-to-video social ads. Use Turbo for cost-sensitive iteration and Gen-4.5 when the client pays for the last increment of polish. See our real-estate and villa battles for logged side-by-side results.